aboutsummaryrefslogtreecommitdiffstats
path: root/fpga/usrp2/opencores/i2c/rtl
diff options
context:
space:
mode:
authorMartin Braun <martin.braun@ettus.com>2020-01-23 16:10:22 -0800
committerMartin Braun <martin.braun@ettus.com>2020-01-28 09:35:36 -0800
commitbafa9d95453387814ef25e6b6256ba8db2df612f (patch)
tree39ba24b5b67072d354775272e687796bb511848d /fpga/usrp2/opencores/i2c/rtl
parent3075b981503002df3115d5f1d0b97d2619ba30f2 (diff)
downloaduhd-bafa9d95453387814ef25e6b6256ba8db2df612f.tar.gz
uhd-bafa9d95453387814ef25e6b6256ba8db2df612f.tar.bz2
uhd-bafa9d95453387814ef25e6b6256ba8db2df612f.zip
Merge FPGA repository back into UHD repository
The FPGA codebase was removed from the UHD repository in 2014 to reduce the size of the repository. However, over the last half-decade, the split between the repositories has proven more burdensome than it has been helpful. By merging the FPGA code back, it will be possible to create atomic commits that touch both FPGA and UHD codebases. Continuous integration testing is also simplified by merging the repositories, because it was previously difficult to automatically derive the correct UHD branch when testing a feature branch on the FPGA repository. This commit also updates the license files and paths therein. We are therefore merging the repositories again. Future development for FPGA code will happen in the same repository as the UHD host code and MPM code. == Original Codebase and Rebasing == The original FPGA repository will be hosted for the foreseeable future at its original local location: https://github.com/EttusResearch/fpga/ It can be used for bisecting, reference, and a more detailed history. The final commit from said repository to be merged here is 05003794e2da61cabf64dd278c45685a7abad7ec. This commit is tagged as v4.0.0.0-pre-uhd-merge. If you have changes in the FPGA repository that you want to rebase onto the UHD repository, simply run the following commands: - Create a directory to store patches (this should be an empty directory): mkdir ~/patches - Now make sure that your FPGA codebase is based on the same state as the code that was merged: cd src/fpga # Or wherever your FPGA code is stored git rebase v4.0.0.0-pre-uhd-merge Note: The rebase command may look slightly different depending on what exactly you're trying to rebase. - Create a patch set for your changes versus v4.0.0.0-pre-uhd-merge: git format-patch v4.0.0.0-pre-uhd-merge -o ~/patches Note: Make sure that only patches are stored in your output directory. It should otherwise be empty. Make sure that you picked the correct range of commits, and only commits you wanted to rebase were exported as patch files. - Go to the UHD repository and apply the patches: cd src/uhd # Or wherever your UHD repository is stored git am --directory fpga ~/patches/* rm -rf ~/patches # This is for cleanup == Contributors == The following people have contributed mainly to these files (this list is not complete): Co-authored-by: Alex Williams <alex.williams@ni.com> Co-authored-by: Andrej Rode <andrej.rode@ettus.com> Co-authored-by: Ashish Chaudhari <ashish@ettus.com> Co-authored-by: Ben Hilburn <ben.hilburn@ettus.com> Co-authored-by: Ciro Nishiguchi <ciro.nishiguchi@ni.com> Co-authored-by: Daniel Jepson <daniel.jepson@ni.com> Co-authored-by: Derek Kozel <derek.kozel@ettus.com> Co-authored-by: EJ Kreinar <ej@he360.com> Co-authored-by: Humberto Jimenez <humberto.jimenez@ni.com> Co-authored-by: Ian Buckley <ian.buckley@gmail.com> Co-authored-by: Jörg Hofrichter <joerg.hofrichter@ni.com> Co-authored-by: Jon Kiser <jon.kiser@ni.com> Co-authored-by: Josh Blum <josh@joshknows.com> Co-authored-by: Jonathon Pendlum <jonathan.pendlum@ettus.com> Co-authored-by: Martin Braun <martin.braun@ettus.com> Co-authored-by: Matt Ettus <matt@ettus.com> Co-authored-by: Michael West <michael.west@ettus.com> Co-authored-by: Moritz Fischer <moritz.fischer@ettus.com> Co-authored-by: Nick Foster <nick@ettus.com> Co-authored-by: Nicolas Cuervo <nicolas.cuervo@ettus.com> Co-authored-by: Paul Butler <paul.butler@ni.com> Co-authored-by: Paul David <paul.david@ettus.com> Co-authored-by: Ryan Marlow <ryan.marlow@ettus.com> Co-authored-by: Sugandha Gupta <sugandha.gupta@ettus.com> Co-authored-by: Sylvain Munaut <tnt@246tNt.com> Co-authored-by: Trung Tran <trung.tran@ettus.com> Co-authored-by: Vidush Vishwanath <vidush.vishwanath@ettus.com> Co-authored-by: Wade Fife <wade.fife@ettus.com>
Diffstat (limited to 'fpga/usrp2/opencores/i2c/rtl')
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_bit_ctrl.v538
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_byte_ctrl.v344
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_defines.v64
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_top.v301
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/verilog/timescale.v2
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD620
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd495
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd370
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_top.vhd359
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/readme25
-rw-r--r--fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd283
11 files changed, 3401 insertions, 0 deletions
diff --git a/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_bit_ctrl.v b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_bit_ctrl.v
new file mode 100644
index 000000000..edab94f61
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_bit_ctrl.v
@@ -0,0 +1,538 @@
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// WISHBONE rev.B2 compliant I2C Master bit-controller ////
+//// ////
+//// ////
+//// Author: Richard Herveille ////
+//// richard@asics.ws ////
+//// www.asics.ws ////
+//// ////
+//// Downloaded from: http://www.opencores.org/projects/i2c/ ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// Copyright (C) 2001 Richard Herveille ////
+//// richard@asics.ws ////
+//// ////
+//// This source file may be used and distributed without ////
+//// restriction provided that this copyright statement is not ////
+//// removed from the file and that any derivative work contains ////
+//// the original copyright notice and the associated disclaimer.////
+//// ////
+//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
+//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////
+//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////
+//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////
+//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////
+//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////
+//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////
+//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////
+//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////
+//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////
+//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////
+//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////
+//// POSSIBILITY OF SUCH DAMAGE. ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+
+// CVS Log
+//
+// $Id: i2c_master_bit_ctrl.v,v 1.12 2006/09/04 09:08:13 rherveille Exp $
+//
+// $Date: 2006/09/04 09:08:13 $
+// $Revision: 1.12 $
+// $Author: rherveille $
+// $Locker: $
+// $State: Exp $
+//
+// Change History:
+// $Log: i2c_master_bit_ctrl.v,v $
+// Revision 1.12 2006/09/04 09:08:13 rherveille
+// fixed short scl high pulse after clock stretch
+// fixed slave model not returning correct '(n)ack' signal
+//
+// Revision 1.11 2004/05/07 11:02:26 rherveille
+// Fixed a bug where the core would signal an arbitration lost (AL bit set), when another master controls the bus and the other master generates a STOP bit.
+//
+// Revision 1.10 2003/08/09 07:01:33 rherveille
+// Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
+// Fixed a potential bug in the byte controller's host-acknowledge generation.
+//
+// Revision 1.9 2003/03/10 14:26:37 rherveille
+// Fixed cmd_ack generation item (no bug).
+//
+// Revision 1.8 2003/02/05 00:06:10 rherveille
+// Fixed a bug where the core would trigger an erroneous 'arbitration lost' interrupt after being reset, when the reset pulse width < 3 clk cycles.
+//
+// Revision 1.7 2002/12/26 16:05:12 rherveille
+// Small code simplifications
+//
+// Revision 1.6 2002/12/26 15:02:32 rherveille
+// Core is now a Multimaster I2C controller
+//
+// Revision 1.5 2002/11/30 22:24:40 rherveille
+// Cleaned up code
+//
+// Revision 1.4 2002/10/30 18:10:07 rherveille
+// Fixed some reported minor start/stop generation timing issuess.
+//
+// Revision 1.3 2002/06/15 07:37:03 rherveille
+// Fixed a small timing bug in the bit controller.\nAdded verilog simulation environment.
+//
+// Revision 1.2 2001/11/05 11:59:25 rherveille
+// Fixed wb_ack_o generation bug.
+// Fixed bug in the byte_controller statemachine.
+// Added headers.
+//
+
+//
+/////////////////////////////////////
+// Bit controller section
+/////////////////////////////////////
+//
+// Translate simple commands into SCL/SDA transitions
+// Each command has 5 states, A/B/C/D/idle
+//
+// start: SCL ~~~~~~~~~~\____
+// SDA ~~~~~~~~\______
+// x | A | B | C | D | i
+//
+// repstart SCL ____/~~~~\___
+// SDA __/~~~\______
+// x | A | B | C | D | i
+//
+// stop SCL ____/~~~~~~~~
+// SDA ==\____/~~~~~
+// x | A | B | C | D | i
+//
+//- write SCL ____/~~~~\____
+// SDA ==X=========X=
+// x | A | B | C | D | i
+//
+//- read SCL ____/~~~~\____
+// SDA XXXX=====XXXX
+// x | A | B | C | D | i
+//
+
+// Timing: Normal mode Fast mode
+///////////////////////////////////////////////////////////////////////
+// Fscl 100KHz 400KHz
+// Th_scl 4.0us 0.6us High period of SCL
+// Tl_scl 4.7us 1.3us Low period of SCL
+// Tsu:sta 4.7us 0.6us setup time for a repeated start condition
+// Tsu:sto 4.0us 0.6us setup time for a stop conditon
+// Tbuf 4.7us 1.3us Bus free time between a stop and start condition
+//
+
+// synopsys translate_off
+`include "timescale.v"
+// synopsys translate_on
+
+`include "i2c_master_defines.v"
+
+module i2c_master_bit_ctrl(
+ clk, rst, nReset,
+ clk_cnt, ena, cmd, cmd_ack, busy, al, din, dout,
+ scl_i, scl_o, scl_oen, sda_i, sda_o, sda_oen
+ );
+
+ //
+ // inputs & outputs
+ //
+ input clk;
+ input rst;
+ input nReset;
+ input ena; // core enable signal
+
+ input [15:0] clk_cnt; // clock prescale value
+
+ input [3:0] cmd;
+ output cmd_ack; // command complete acknowledge
+ reg cmd_ack;
+ output busy; // i2c bus busy
+ reg busy;
+ output al; // i2c bus arbitration lost
+ reg al;
+
+ input din;
+ output dout;
+ reg dout;
+
+ // I2C lines
+ input scl_i; // i2c clock line input
+ output scl_o; // i2c clock line output
+ output scl_oen; // i2c clock line output enable (active low)
+ reg scl_oen;
+ input sda_i; // i2c data line input
+ output sda_o; // i2c data line output
+ output sda_oen; // i2c data line output enable (active low)
+ reg sda_oen;
+
+
+ //
+ // variable declarations
+ //
+
+ reg sSCL, sSDA; // synchronized SCL and SDA inputs
+ reg dscl_oen; // delayed scl_oen
+ reg sda_chk; // check SDA output (Multi-master arbitration)
+ reg clk_en; // clock generation signals
+ wire slave_wait;
+// reg [15:0] cnt = clk_cnt; // clock divider counter (simulation)
+ reg [15:0] cnt; // clock divider counter (synthesis)
+
+ // state machine variable
+ reg [16:0] c_state; // synopsys enum_state
+
+ //
+ // module body
+ //
+
+ // whenever the slave is not ready it can delay the cycle by pulling SCL low
+ // delay scl_oen
+ always @(posedge clk)
+ dscl_oen <= #1 scl_oen;
+
+ assign slave_wait = dscl_oen && !sSCL;
+
+
+ // generate clk enable signal
+ always @(posedge clk or negedge nReset)
+ if(~nReset)
+ begin
+ cnt <= #1 16'h0;
+ clk_en <= #1 1'b1;
+ end
+ else if (rst)
+ begin
+ cnt <= #1 16'h0;
+ clk_en <= #1 1'b1;
+ end
+ else if ( ~|cnt || !ena)
+ begin
+ cnt <= #1 clk_cnt;
+ clk_en <= #1 1'b1;
+ end
+ else if (slave_wait)
+ begin
+ cnt <= #1 cnt;
+ clk_en <= #1 1'b0;
+ end
+ else
+ begin
+ cnt <= #1 cnt - 16'h1;
+ clk_en <= #1 1'b0;
+ end
+
+
+ // generate bus status controller
+ reg dSCL, dSDA;
+ reg sta_condition;
+ reg sto_condition;
+
+ // synchronize SCL and SDA inputs
+ // reduce metastability risc
+ always @(posedge clk or negedge nReset)
+ if (~nReset)
+ begin
+ sSCL <= #1 1'b1;
+ sSDA <= #1 1'b1;
+
+ dSCL <= #1 1'b1;
+ dSDA <= #1 1'b1;
+ end
+ else if (rst)
+ begin
+ sSCL <= #1 1'b1;
+ sSDA <= #1 1'b1;
+
+ dSCL <= #1 1'b1;
+ dSDA <= #1 1'b1;
+ end
+ else
+ begin
+ sSCL <= #1 scl_i;
+ sSDA <= #1 sda_i;
+
+ dSCL <= #1 sSCL;
+ dSDA <= #1 sSDA;
+ end
+
+ // detect start condition => detect falling edge on SDA while SCL is high
+ // detect stop condition => detect rising edge on SDA while SCL is high
+ always @(posedge clk or negedge nReset)
+ if (~nReset)
+ begin
+ sta_condition <= #1 1'b0;
+ sto_condition <= #1 1'b0;
+ end
+ else if (rst)
+ begin
+ sta_condition <= #1 1'b0;
+ sto_condition <= #1 1'b0;
+ end
+ else
+ begin
+ sta_condition <= #1 ~sSDA & dSDA & sSCL;
+ sto_condition <= #1 sSDA & ~dSDA & sSCL;
+ end
+
+ // generate i2c bus busy signal
+ always @(posedge clk or negedge nReset)
+ if(!nReset)
+ busy <= #1 1'b0;
+ else if (rst)
+ busy <= #1 1'b0;
+ else
+ busy <= #1 (sta_condition | busy) & ~sto_condition;
+
+ // generate arbitration lost signal
+ // aribitration lost when:
+ // 1) master drives SDA high, but the i2c bus is low
+ // 2) stop detected while not requested
+ reg cmd_stop;
+ always @(posedge clk or negedge nReset)
+ if (~nReset)
+ cmd_stop <= #1 1'b0;
+ else if (rst)
+ cmd_stop <= #1 1'b0;
+ else if (clk_en)
+ cmd_stop <= #1 cmd == `I2C_CMD_STOP;
+
+ always @(posedge clk or negedge nReset)
+ if (~nReset)
+ al <= #1 1'b0;
+ else if (rst)
+ al <= #1 1'b0;
+ else
+ al <= #1 (sda_chk & ~sSDA & sda_oen) | (|c_state & sto_condition & ~cmd_stop);
+
+
+ // generate dout signal (store SDA on rising edge of SCL)
+ always @(posedge clk)
+ if(sSCL & ~dSCL)
+ dout <= #1 sSDA;
+
+ // generate statemachine
+
+ // nxt_state decoder
+ parameter [16:0] idle = 17'b0_0000_0000_0000_0000;
+ parameter [16:0] start_a = 17'b0_0000_0000_0000_0001;
+ parameter [16:0] start_b = 17'b0_0000_0000_0000_0010;
+ parameter [16:0] start_c = 17'b0_0000_0000_0000_0100;
+ parameter [16:0] start_d = 17'b0_0000_0000_0000_1000;
+ parameter [16:0] start_e = 17'b0_0000_0000_0001_0000;
+ parameter [16:0] stop_a = 17'b0_0000_0000_0010_0000;
+ parameter [16:0] stop_b = 17'b0_0000_0000_0100_0000;
+ parameter [16:0] stop_c = 17'b0_0000_0000_1000_0000;
+ parameter [16:0] stop_d = 17'b0_0000_0001_0000_0000;
+ parameter [16:0] rd_a = 17'b0_0000_0010_0000_0000;
+ parameter [16:0] rd_b = 17'b0_0000_0100_0000_0000;
+ parameter [16:0] rd_c = 17'b0_0000_1000_0000_0000;
+ parameter [16:0] rd_d = 17'b0_0001_0000_0000_0000;
+ parameter [16:0] wr_a = 17'b0_0010_0000_0000_0000;
+ parameter [16:0] wr_b = 17'b0_0100_0000_0000_0000;
+ parameter [16:0] wr_c = 17'b0_1000_0000_0000_0000;
+ parameter [16:0] wr_d = 17'b1_0000_0000_0000_0000;
+
+ always @(posedge clk or negedge nReset)
+ if (!nReset)
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b0;
+ scl_oen <= #1 1'b1;
+ sda_oen <= #1 1'b1;
+ sda_chk <= #1 1'b0;
+ end
+ else if (rst | al)
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b0;
+ scl_oen <= #1 1'b1;
+ sda_oen <= #1 1'b1;
+ sda_chk <= #1 1'b0;
+ end
+ else
+ begin
+ cmd_ack <= #1 1'b0; // default no command acknowledge + assert cmd_ack only 1clk cycle
+
+ if (clk_en)
+ case (c_state) // synopsys full_case parallel_case
+ // idle state
+ idle:
+ begin
+ case (cmd) // synopsys full_case parallel_case
+ `I2C_CMD_START:
+ c_state <= #1 start_a;
+
+ `I2C_CMD_STOP:
+ c_state <= #1 stop_a;
+
+ `I2C_CMD_WRITE:
+ c_state <= #1 wr_a;
+
+ `I2C_CMD_READ:
+ c_state <= #1 rd_a;
+
+ default:
+ c_state <= #1 idle;
+ endcase
+
+ scl_oen <= #1 scl_oen; // keep SCL in same state
+ sda_oen <= #1 sda_oen; // keep SDA in same state
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ // start
+ start_a:
+ begin
+ c_state <= #1 start_b;
+ scl_oen <= #1 scl_oen; // keep SCL in same state
+ sda_oen <= #1 1'b1; // set SDA high
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ start_b:
+ begin
+ c_state <= #1 start_c;
+ scl_oen <= #1 1'b1; // set SCL high
+ sda_oen <= #1 1'b1; // keep SDA high
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ start_c:
+ begin
+ c_state <= #1 start_d;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 1'b0; // set SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ start_d:
+ begin
+ c_state <= #1 start_e;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 1'b0; // keep SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ start_e:
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b1;
+ scl_oen <= #1 1'b0; // set SCL low
+ sda_oen <= #1 1'b0; // keep SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ // stop
+ stop_a:
+ begin
+ c_state <= #1 stop_b;
+ scl_oen <= #1 1'b0; // keep SCL low
+ sda_oen <= #1 1'b0; // set SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ stop_b:
+ begin
+ c_state <= #1 stop_c;
+ scl_oen <= #1 1'b1; // set SCL high
+ sda_oen <= #1 1'b0; // keep SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ stop_c:
+ begin
+ c_state <= #1 stop_d;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 1'b0; // keep SDA low
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ stop_d:
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b1;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 1'b1; // set SDA high
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ // read
+ rd_a:
+ begin
+ c_state <= #1 rd_b;
+ scl_oen <= #1 1'b0; // keep SCL low
+ sda_oen <= #1 1'b1; // tri-state SDA
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ rd_b:
+ begin
+ c_state <= #1 rd_c;
+ scl_oen <= #1 1'b1; // set SCL high
+ sda_oen <= #1 1'b1; // keep SDA tri-stated
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ rd_c:
+ begin
+ c_state <= #1 rd_d;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 1'b1; // keep SDA tri-stated
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ rd_d:
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b1;
+ scl_oen <= #1 1'b0; // set SCL low
+ sda_oen <= #1 1'b1; // keep SDA tri-stated
+ sda_chk <= #1 1'b0; // don't check SDA output
+ end
+
+ // write
+ wr_a:
+ begin
+ c_state <= #1 wr_b;
+ scl_oen <= #1 1'b0; // keep SCL low
+ sda_oen <= #1 din; // set SDA
+ sda_chk <= #1 1'b0; // don't check SDA output (SCL low)
+ end
+
+ wr_b:
+ begin
+ c_state <= #1 wr_c;
+ scl_oen <= #1 1'b1; // set SCL high
+ sda_oen <= #1 din; // keep SDA
+ sda_chk <= #1 1'b1; // check SDA output
+ end
+
+ wr_c:
+ begin
+ c_state <= #1 wr_d;
+ scl_oen <= #1 1'b1; // keep SCL high
+ sda_oen <= #1 din;
+ sda_chk <= #1 1'b1; // check SDA output
+ end
+
+ wr_d:
+ begin
+ c_state <= #1 idle;
+ cmd_ack <= #1 1'b1;
+ scl_oen <= #1 1'b0; // set SCL low
+ sda_oen <= #1 din;
+ sda_chk <= #1 1'b0; // don't check SDA output (SCL low)
+ end
+
+ endcase
+ end
+
+
+ // assign scl and sda output (always gnd)
+ assign scl_o = 1'b0;
+ assign sda_o = 1'b0;
+
+endmodule
diff --git a/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_byte_ctrl.v b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_byte_ctrl.v
new file mode 100644
index 000000000..d091d1e36
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_byte_ctrl.v
@@ -0,0 +1,344 @@
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// WISHBONE rev.B2 compliant I2C Master byte-controller ////
+//// ////
+//// ////
+//// Author: Richard Herveille ////
+//// richard@asics.ws ////
+//// www.asics.ws ////
+//// ////
+//// Downloaded from: http://www.opencores.org/projects/i2c/ ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// Copyright (C) 2001 Richard Herveille ////
+//// richard@asics.ws ////
+//// ////
+//// This source file may be used and distributed without ////
+//// restriction provided that this copyright statement is not ////
+//// removed from the file and that any derivative work contains ////
+//// the original copyright notice and the associated disclaimer.////
+//// ////
+//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
+//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////
+//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////
+//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////
+//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////
+//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////
+//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////
+//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////
+//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////
+//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////
+//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////
+//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////
+//// POSSIBILITY OF SUCH DAMAGE. ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+
+// CVS Log
+//
+// $Id: i2c_master_byte_ctrl.v,v 1.7 2004/02/18 11:40:46 rherveille Exp $
+//
+// $Date: 2004/02/18 11:40:46 $
+// $Revision: 1.7 $
+// $Author: rherveille $
+// $Locker: $
+// $State: Exp $
+//
+// Change History:
+// $Log: i2c_master_byte_ctrl.v,v $
+// Revision 1.7 2004/02/18 11:40:46 rherveille
+// Fixed a potential bug in the statemachine. During a 'stop' 2 cmd_ack signals were generated. Possibly canceling a new start command.
+//
+// Revision 1.6 2003/08/09 07:01:33 rherveille
+// Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
+// Fixed a potential bug in the byte controller's host-acknowledge generation.
+//
+// Revision 1.5 2002/12/26 15:02:32 rherveille
+// Core is now a Multimaster I2C controller
+//
+// Revision 1.4 2002/11/30 22:24:40 rherveille
+// Cleaned up code
+//
+// Revision 1.3 2001/11/05 11:59:25 rherveille
+// Fixed wb_ack_o generation bug.
+// Fixed bug in the byte_controller statemachine.
+// Added headers.
+//
+
+// synopsys translate_off
+`include "timescale.v"
+// synopsys translate_on
+
+`include "i2c_master_defines.v"
+
+module i2c_master_byte_ctrl (
+ clk, rst, nReset, ena, clk_cnt, start, stop, read, write, ack_in, din,
+ cmd_ack, ack_out, dout, i2c_busy, i2c_al, scl_i, scl_o, scl_oen, sda_i, sda_o, sda_oen );
+
+ //
+ // inputs & outputs
+ //
+ input clk; // master clock
+ input rst; // synchronous active high reset
+ input nReset; // asynchronous active low reset
+ input ena; // core enable signal
+
+ input [15:0] clk_cnt; // 4x SCL
+
+ // control inputs
+ input start;
+ input stop;
+ input read;
+ input write;
+ input ack_in;
+ input [7:0] din;
+
+ // status outputs
+ output cmd_ack;
+ reg cmd_ack;
+ output ack_out;
+ reg ack_out;
+ output i2c_busy;
+ output i2c_al;
+ output [7:0] dout;
+
+ // I2C signals
+ input scl_i;
+ output scl_o;
+ output scl_oen;
+ input sda_i;
+ output sda_o;
+ output sda_oen;
+
+
+ //
+ // Variable declarations
+ //
+
+ // statemachine
+ parameter [4:0] ST_IDLE = 5'b0_0000;
+ parameter [4:0] ST_START = 5'b0_0001;
+ parameter [4:0] ST_READ = 5'b0_0010;
+ parameter [4:0] ST_WRITE = 5'b0_0100;
+ parameter [4:0] ST_ACK = 5'b0_1000;
+ parameter [4:0] ST_STOP = 5'b1_0000;
+
+ // signals for bit_controller
+ reg [3:0] core_cmd;
+ reg core_txd;
+ wire core_ack, core_rxd;
+
+ // signals for shift register
+ reg [7:0] sr; //8bit shift register
+ reg shift, ld;
+
+ // signals for state machine
+ wire go;
+ reg [2:0] dcnt;
+ wire cnt_done;
+
+ //
+ // Module body
+ //
+
+ // hookup bit_controller
+ i2c_master_bit_ctrl bit_controller (
+ .clk ( clk ),
+ .rst ( rst ),
+ .nReset ( nReset ),
+ .ena ( ena ),
+ .clk_cnt ( clk_cnt ),
+ .cmd ( core_cmd ),
+ .cmd_ack ( core_ack ),
+ .busy ( i2c_busy ),
+ .al ( i2c_al ),
+ .din ( core_txd ),
+ .dout ( core_rxd ),
+ .scl_i ( scl_i ),
+ .scl_o ( scl_o ),
+ .scl_oen ( scl_oen ),
+ .sda_i ( sda_i ),
+ .sda_o ( sda_o ),
+ .sda_oen ( sda_oen )
+ );
+
+ // generate go-signal
+ assign go = (read | write | stop) & ~cmd_ack;
+
+ // assign dout output to shift-register
+ assign dout = sr;
+
+ // generate shift register
+ always @(posedge clk or negedge nReset)
+ if (!nReset)
+ sr <= #1 8'h0;
+ else if (rst)
+ sr <= #1 8'h0;
+ else if (ld)
+ sr <= #1 din;
+ else if (shift)
+ sr <= #1 {sr[6:0], core_rxd};
+
+ // generate counter
+ always @(posedge clk or negedge nReset)
+ if (!nReset)
+ dcnt <= #1 3'h0;
+ else if (rst)
+ dcnt <= #1 3'h0;
+ else if (ld)
+ dcnt <= #1 3'h7;
+ else if (shift)
+ dcnt <= #1 dcnt - 3'h1;
+
+ assign cnt_done = ~(|dcnt);
+
+ //
+ // state machine
+ //
+ reg [4:0] c_state; // synopsis enum_state
+
+ always @(posedge clk or negedge nReset)
+ if (!nReset)
+ begin
+ core_cmd <= #1 `I2C_CMD_NOP;
+ core_txd <= #1 1'b0;
+ shift <= #1 1'b0;
+ ld <= #1 1'b0;
+ cmd_ack <= #1 1'b0;
+ c_state <= #1 ST_IDLE;
+ ack_out <= #1 1'b0;
+ end
+ else if (rst | i2c_al)
+ begin
+ core_cmd <= #1 `I2C_CMD_NOP;
+ core_txd <= #1 1'b0;
+ shift <= #1 1'b0;
+ ld <= #1 1'b0;
+ cmd_ack <= #1 1'b0;
+ c_state <= #1 ST_IDLE;
+ ack_out <= #1 1'b0;
+ end
+ else
+ begin
+ // initially reset all signals
+ core_txd <= #1 sr[7];
+ shift <= #1 1'b0;
+ ld <= #1 1'b0;
+ cmd_ack <= #1 1'b0;
+
+ case (c_state) // synopsys full_case parallel_case
+ ST_IDLE:
+ if (go)
+ begin
+ if (start)
+ begin
+ c_state <= #1 ST_START;
+ core_cmd <= #1 `I2C_CMD_START;
+ end
+ else if (read)
+ begin
+ c_state <= #1 ST_READ;
+ core_cmd <= #1 `I2C_CMD_READ;
+ end
+ else if (write)
+ begin
+ c_state <= #1 ST_WRITE;
+ core_cmd <= #1 `I2C_CMD_WRITE;
+ end
+ else // stop
+ begin
+ c_state <= #1 ST_STOP;
+ core_cmd <= #1 `I2C_CMD_STOP;
+ end
+
+ ld <= #1 1'b1;
+ end
+
+ ST_START:
+ if (core_ack)
+ begin
+ if (read)
+ begin
+ c_state <= #1 ST_READ;
+ core_cmd <= #1 `I2C_CMD_READ;
+ end
+ else
+ begin
+ c_state <= #1 ST_WRITE;
+ core_cmd <= #1 `I2C_CMD_WRITE;
+ end
+
+ ld <= #1 1'b1;
+ end
+
+ ST_WRITE:
+ if (core_ack)
+ if (cnt_done)
+ begin
+ c_state <= #1 ST_ACK;
+ core_cmd <= #1 `I2C_CMD_READ;
+ end
+ else
+ begin
+ c_state <= #1 ST_WRITE; // stay in same state
+ core_cmd <= #1 `I2C_CMD_WRITE; // write next bit
+ shift <= #1 1'b1;
+ end
+
+ ST_READ:
+ if (core_ack)
+ begin
+ if (cnt_done)
+ begin
+ c_state <= #1 ST_ACK;
+ core_cmd <= #1 `I2C_CMD_WRITE;
+ end
+ else
+ begin
+ c_state <= #1 ST_READ; // stay in same state
+ core_cmd <= #1 `I2C_CMD_READ; // read next bit
+ end
+
+ shift <= #1 1'b1;
+ core_txd <= #1 ack_in;
+ end
+
+ ST_ACK:
+ if (core_ack)
+ begin
+ if (stop)
+ begin
+ c_state <= #1 ST_STOP;
+ core_cmd <= #1 `I2C_CMD_STOP;
+ end
+ else
+ begin
+ c_state <= #1 ST_IDLE;
+ core_cmd <= #1 `I2C_CMD_NOP;
+
+ // generate command acknowledge signal
+ cmd_ack <= #1 1'b1;
+ end
+
+ // assign ack_out output to bit_controller_rxd (contains last received bit)
+ ack_out <= #1 core_rxd;
+
+ core_txd <= #1 1'b1;
+ end
+ else
+ core_txd <= #1 ack_in;
+
+ ST_STOP:
+ if (core_ack)
+ begin
+ c_state <= #1 ST_IDLE;
+ core_cmd <= #1 `I2C_CMD_NOP;
+
+ // generate command acknowledge signal
+ cmd_ack <= #1 1'b1;
+ end
+
+ endcase
+ end
+endmodule
diff --git a/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_defines.v b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_defines.v
new file mode 100644
index 000000000..ee3b694fa
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_defines.v
@@ -0,0 +1,64 @@
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// WISHBONE rev.B2 compliant I2C Master controller defines ////
+//// ////
+//// ////
+//// Author: Richard Herveille ////
+//// richard@asics.ws ////
+//// www.asics.ws ////
+//// ////
+//// Downloaded from: http://www.opencores.org/projects/i2c/ ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// Copyright (C) 2001 Richard Herveille ////
+//// richard@asics.ws ////
+//// ////
+//// This source file may be used and distributed without ////
+//// restriction provided that this copyright statement is not ////
+//// removed from the file and that any derivative work contains ////
+//// the original copyright notice and the associated disclaimer.////
+//// ////
+//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
+//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////
+//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////
+//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////
+//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////
+//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////
+//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////
+//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////
+//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////
+//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////
+//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////
+//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////
+//// POSSIBILITY OF SUCH DAMAGE. ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+
+// CVS Log
+//
+// $Id: i2c_master_defines.v,v 1.3 2001/11/05 11:59:25 rherveille Exp $
+//
+// $Date: 2001/11/05 11:59:25 $
+// $Revision: 1.3 $
+// $Author: rherveille $
+// $Locker: $
+// $State: Exp $
+//
+// Change History:
+// $Log: i2c_master_defines.v,v $
+// Revision 1.3 2001/11/05 11:59:25 rherveille
+// Fixed wb_ack_o generation bug.
+// Fixed bug in the byte_controller statemachine.
+// Added headers.
+//
+
+
+// I2C registers wishbone addresses
+
+// bitcontroller states
+`define I2C_CMD_NOP 4'b0000
+`define I2C_CMD_START 4'b0001
+`define I2C_CMD_STOP 4'b0010
+`define I2C_CMD_WRITE 4'b0100
+`define I2C_CMD_READ 4'b1000
diff --git a/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_top.v b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_top.v
new file mode 100644
index 000000000..30689bd70
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/verilog/i2c_master_top.v
@@ -0,0 +1,301 @@
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// WISHBONE revB.2 compliant I2C Master controller Top-level ////
+//// ////
+//// ////
+//// Author: Richard Herveille ////
+//// richard@asics.ws ////
+//// www.asics.ws ////
+//// ////
+//// Downloaded from: http://www.opencores.org/projects/i2c/ ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+//// ////
+//// Copyright (C) 2001 Richard Herveille ////
+//// richard@asics.ws ////
+//// ////
+//// This source file may be used and distributed without ////
+//// restriction provided that this copyright statement is not ////
+//// removed from the file and that any derivative work contains ////
+//// the original copyright notice and the associated disclaimer.////
+//// ////
+//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
+//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////
+//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////
+//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////
+//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////
+//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////
+//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////
+//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////
+//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////
+//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////
+//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////
+//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////
+//// POSSIBILITY OF SUCH DAMAGE. ////
+//// ////
+/////////////////////////////////////////////////////////////////////
+
+// CVS Log
+//
+// $Id: i2c_master_top.v,v 1.11 2005/02/27 09:26:24 rherveille Exp $
+//
+// $Date: 2005/02/27 09:26:24 $
+// $Revision: 1.11 $
+// $Author: rherveille $
+// $Locker: $
+// $State: Exp $
+//
+// Change History:
+// $Log: i2c_master_top.v,v $
+// Revision 1.11 2005/02/27 09:26:24 rherveille
+// Fixed register overwrite issue.
+// Removed full_case pragma, replaced it by a default statement.
+//
+// Revision 1.10 2003/09/01 10:34:38 rherveille
+// Fix a blocking vs. non-blocking error in the wb_dat output mux.
+//
+// Revision 1.9 2003/01/09 16:44:45 rherveille
+// Fixed a bug in the Command Register declaration.
+//
+// Revision 1.8 2002/12/26 16:05:12 rherveille
+// Small code simplifications
+//
+// Revision 1.7 2002/12/26 15:02:32 rherveille
+// Core is now a Multimaster I2C controller
+//
+// Revision 1.6 2002/11/30 22:24:40 rherveille
+// Cleaned up code
+//
+// Revision 1.5 2001/11/10 10:52:55 rherveille
+// Changed PRER reset value from 0x0000 to 0xffff, conform specs.
+//
+
+// synopsys translate_off
+`include "timescale.v"
+// synopsys translate_on
+
+`include "i2c_master_defines.v"
+
+module i2c_master_top(
+ wb_clk_i, wb_rst_i, arst_i, wb_adr_i, wb_dat_i, wb_dat_o,
+ wb_we_i, wb_stb_i, wb_cyc_i, wb_ack_o, wb_inta_o,
+ scl_pad_i, scl_pad_o, scl_padoen_o, sda_pad_i, sda_pad_o, sda_padoen_o );
+
+ // parameters
+ parameter ARST_LVL = 1'b0; // asynchronous reset level
+
+ //
+ // inputs & outputs
+ //
+
+ // wishbone signals
+ input wb_clk_i; // master clock input
+ input wb_rst_i; // synchronous active high reset
+ input arst_i; // asynchronous reset
+ input [2:0] wb_adr_i; // lower address bits
+ input [7:0] wb_dat_i; // databus input
+ output [7:0] wb_dat_o; // databus output
+ input wb_we_i; // write enable input
+ input wb_stb_i; // stobe/core select signal
+ input wb_cyc_i; // valid bus cycle input
+ output wb_ack_o; // bus cycle acknowledge output
+ output wb_inta_o; // interrupt request signal output
+
+ reg [7:0] wb_dat_o;
+ reg wb_ack_o;
+ reg wb_inta_o;
+
+ // I2C signals
+ // i2c clock line
+ input scl_pad_i; // SCL-line input
+ output scl_pad_o; // SCL-line output (always 1'b0)
+ output scl_padoen_o; // SCL-line output enable (active low)
+
+ // i2c data line
+ input sda_pad_i; // SDA-line input
+ output sda_pad_o; // SDA-line output (always 1'b0)
+ output sda_padoen_o; // SDA-line output enable (active low)
+
+
+ //
+ // variable declarations
+ //
+
+ // registers
+ reg [15:0] prer; // clock prescale register
+ reg [ 7:0] ctr; // control register
+ reg [ 7:0] txr; // transmit register
+ wire [ 7:0] rxr; // receive register
+ reg [ 7:0] cr; // command register
+ wire [ 7:0] sr; // status register
+
+ // done signal: command completed, clear command register
+ wire done;
+
+ // core enable signal
+ wire core_en;
+ wire ien;
+
+ // status register signals
+ wire irxack;
+ reg rxack; // received aknowledge from slave
+ reg tip; // transfer in progress
+ reg irq_flag; // interrupt pending flag
+ wire i2c_busy; // bus busy (start signal detected)
+ wire i2c_al; // i2c bus arbitration lost
+ reg al; // status register arbitration lost bit
+
+ //
+ // module body
+ //
+
+ // generate internal reset
+ wire rst_i = arst_i ^ ARST_LVL;
+
+ // generate wishbone signals
+ wire wb_wacc = wb_cyc_i & wb_stb_i & wb_we_i;
+
+ // generate acknowledge output signal
+ always @(posedge wb_clk_i)
+ wb_ack_o <= #1 wb_cyc_i & wb_stb_i & ~wb_ack_o; // because timing is always honored
+
+ // assign DAT_O
+ always @(posedge wb_clk_i)
+ begin
+ case (wb_adr_i) // synopsis parallel_case
+ 3'b000: wb_dat_o <= #1 prer[ 7:0];
+ 3'b001: wb_dat_o <= #1 prer[15:8];
+ 3'b010: wb_dat_o <= #1 ctr;
+ 3'b011: wb_dat_o <= #1 rxr; // write is transmit register (txr)
+ 3'b100: wb_dat_o <= #1 sr; // write is command register (cr)
+ 3'b101: wb_dat_o <= #1 txr;
+ 3'b110: wb_dat_o <= #1 cr;
+ 3'b111: wb_dat_o <= #1 0; // reserved
+ endcase
+ end
+
+ // generate registers
+ always @(posedge wb_clk_i or negedge rst_i)
+ if (!rst_i)
+ begin
+ prer <= #1 16'hffff;
+ ctr <= #1 8'h0;
+ txr <= #1 8'h0;
+ end
+ else if (wb_rst_i)
+ begin
+ prer <= #1 16'hffff;
+ ctr <= #1 8'h0;
+ txr <= #1 8'h0;
+ end
+ else
+ if (wb_wacc)
+ case (wb_adr_i) // synopsis parallel_case
+ 3'b000 : prer [ 7:0] <= #1 wb_dat_i;
+ 3'b001 : prer [15:8] <= #1 wb_dat_i;
+ 3'b010 : ctr <= #1 wb_dat_i;
+ 3'b011 : txr <= #1 wb_dat_i;
+ default: ;
+ endcase
+
+ // generate command register (special case)
+ always @(posedge wb_clk_i or negedge rst_i)
+ if (~rst_i)
+ cr <= #1 8'h0;
+ else if (wb_rst_i)
+ cr <= #1 8'h0;
+ else if (wb_wacc)
+ begin
+ if (core_en & (wb_adr_i == 3'b100) )
+ cr <= #1 wb_dat_i;
+ end
+ else
+ begin
+ if (done | i2c_al)
+ cr[7:4] <= #1 4'h0; // clear command bits when done
+ // or when aribitration lost
+ cr[2:1] <= #1 2'b0; // reserved bits
+ cr[0] <= #1 2'b0; // clear IRQ_ACK bit
+ end
+
+
+ // decode command register
+ wire sta = cr[7];
+ wire sto = cr[6];
+ wire rd = cr[5];
+ wire wr = cr[4];
+ wire ack = cr[3];
+ wire iack = cr[0];
+
+ // decode control register
+ assign core_en = ctr[7];
+ assign ien = ctr[6];
+
+ // hookup byte controller block
+ i2c_master_byte_ctrl byte_controller (
+ .clk ( wb_clk_i ),
+ .rst ( wb_rst_i ),
+ .nReset ( rst_i ),
+ .ena ( core_en ),
+ .clk_cnt ( prer ),
+ .start ( sta ),
+ .stop ( sto ),
+ .read ( rd ),
+ .write ( wr ),
+ .ack_in ( ack ),
+ .din ( txr ),
+ .cmd_ack ( done ),
+ .ack_out ( irxack ),
+ .dout ( rxr ),
+ .i2c_busy ( i2c_busy ),
+ .i2c_al ( i2c_al ),
+ .scl_i ( scl_pad_i ),
+ .scl_o ( scl_pad_o ),
+ .scl_oen ( scl_padoen_o ),
+ .sda_i ( sda_pad_i ),
+ .sda_o ( sda_pad_o ),
+ .sda_oen ( sda_padoen_o )
+ );
+
+ // status register block + interrupt request signal
+ always @(posedge wb_clk_i or negedge rst_i)
+ if (!rst_i)
+ begin
+ al <= #1 1'b0;
+ rxack <= #1 1'b0;
+ tip <= #1 1'b0;
+ irq_flag <= #1 1'b0;
+ end
+ else if (wb_rst_i)
+ begin
+ al <= #1 1'b0;
+ rxack <= #1 1'b0;
+ tip <= #1 1'b0;
+ irq_flag <= #1 1'b0;
+ end
+ else
+ begin
+ al <= #1 i2c_al | (al & ~sta);
+ rxack <= #1 irxack;
+ tip <= #1 (rd | wr);
+ irq_flag <= #1 (done | i2c_al | irq_flag) & ~iack; // interrupt request flag is always generated
+ end
+
+ // generate interrupt request signals
+ always @(posedge wb_clk_i or negedge rst_i)
+ if (!rst_i)
+ wb_inta_o <= #1 1'b0;
+ else if (wb_rst_i)
+ wb_inta_o <= #1 1'b0;
+ else
+ wb_inta_o <= #1 irq_flag && ien; // interrupt signal is only generated when IEN (interrupt enable bit is set)
+
+ // assign status register bits
+ assign sr[7] = rxack;
+ assign sr[6] = i2c_busy;
+ assign sr[5] = al;
+ assign sr[4:2] = 3'h0; // reserved
+ assign sr[1] = tip;
+ assign sr[0] = irq_flag;
+
+endmodule
diff --git a/fpga/usrp2/opencores/i2c/rtl/verilog/timescale.v b/fpga/usrp2/opencores/i2c/rtl/verilog/timescale.v
new file mode 100644
index 000000000..60d4ecbd1
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/verilog/timescale.v
@@ -0,0 +1,2 @@
+`timescale 1ns / 10ps
+
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD b/fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD
new file mode 100644
index 000000000..64d1eb656
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD
@@ -0,0 +1,620 @@
+--
+-- Simple I2C controller
+--
+-- 1) No multimaster
+-- 2) No slave mode
+-- 3) No fifo's
+--
+-- notes:
+-- Every command is acknowledged. Do not set a new command before previous is acknowledged.
+-- Dout is available 1 clock cycle later as cmd_ack
+--
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+package I2C is
+ component simple_i2c is
+ port (
+ clk : in std_logic;
+ ena : in std_logic;
+ nReset : in std_logic;
+
+ clk_cnt : in unsigned(7 downto 0); -- 4x SCL
+
+ -- input signals
+ start,
+ stop,
+ read,
+ write,
+ ack_in : std_logic;
+ Din : in std_logic_vector(7 downto 0);
+
+ -- output signals
+ cmd_ack : out std_logic;
+ ack_out : out std_logic;
+ Dout : out std_logic_vector(7 downto 0);
+
+ -- i2c signals
+ SCL : inout std_logic;
+ SDA : inout std_logic
+ );
+ end component simple_i2c;
+end package I2C;
+
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+entity simple_i2c is
+ port (
+ clk : in std_logic;
+ ena : in std_logic;
+ nReset : in std_logic;
+
+ clk_cnt : in unsigned(7 downto 0); -- 4x SCL
+
+ -- input signals
+ start,
+ stop,
+ read,
+ write,
+ ack_in : std_logic;
+ Din : in std_logic_vector(7 downto 0);
+
+ -- output signals
+ cmd_ack : out std_logic;
+ ack_out : out std_logic;
+ Dout : out std_logic_vector(7 downto 0);
+
+ -- i2c signals
+ SCL : inout std_logic;
+ SDA : inout std_logic
+ );
+end entity simple_i2c;
+
+architecture structural of simple_i2c is
+ component i2c_core is
+ port (
+ clk : in std_logic;
+ nReset : in std_logic;
+
+ clk_cnt : in unsigned(7 downto 0);
+
+ cmd : in std_logic_vector(2 downto 0);
+ cmd_ack : out std_logic;
+ busy : out std_logic;
+
+ Din : in std_logic;
+ Dout : out std_logic;
+
+ SCL : inout std_logic;
+ SDA : inout std_logic
+ );
+ end component i2c_core;
+
+ -- commands for i2c_core
+ constant CMD_NOP : std_logic_vector(2 downto 0) := "000";
+ constant CMD_START : std_logic_vector(2 downto 0) := "010";
+ constant CMD_STOP : std_logic_vector(2 downto 0) := "011";
+ constant CMD_READ : std_logic_vector(2 downto 0) := "100";
+ constant CMD_WRITE : std_logic_vector(2 downto 0) := "101";
+
+ -- signals for i2c_core
+ signal core_cmd : std_logic_vector(2 downto 0);
+ signal core_ack, core_busy, core_txd, core_rxd : std_logic;
+
+ -- signals for shift register
+ signal sr : std_logic_vector(7 downto 0); -- 8bit shift register
+ signal shift, ld : std_logic;
+
+ -- signals for state machine
+ signal go, host_ack : std_logic;
+begin
+ -- hookup i2c core
+ u1: i2c_core port map (clk, nReset, clk_cnt, core_cmd, core_ack, core_busy, core_txd, core_rxd, SCL, SDA);
+
+ -- generate host-command-acknowledge
+ cmd_ack <= host_ack;
+
+ -- generate go-signal
+ go <= (read or write) and not host_ack;
+
+ -- assign Dout output to shift-register
+ Dout <= sr;
+
+ -- assign ack_out output to core_rxd (contains last received bit)
+ ack_out <= core_rxd;
+
+ -- generate shift register
+ shift_register: process(clk)
+ begin
+ if (clk'event and clk = '1') then
+ if (ld = '1') then
+ sr <= din;
+ elsif (shift = '1') then
+ sr <= (sr(6 downto 0) & core_rxd);
+ end if;
+ end if;
+ end process shift_register;
+
+ --
+ -- state machine
+ --
+ statemachine : block
+ type states is (st_idle, st_start, st_read, st_write, st_ack, st_stop);
+ signal state : states;
+ signal dcnt : unsigned(2 downto 0);
+ begin
+ --
+ -- command interpreter, translate complex commands into simpler I2C commands
+ --
+ nxt_state_decoder: process(clk, nReset, state)
+ variable nxt_state : states;
+ variable idcnt : unsigned(2 downto 0);
+ variable ihost_ack : std_logic;
+ variable icore_cmd : std_logic_vector(2 downto 0);
+ variable icore_txd : std_logic;
+ variable ishift, iload : std_logic;
+ begin
+ -- 8 databits (1byte) of data to shift-in/out
+ idcnt := dcnt;
+
+ -- no acknowledge (until command complete)
+ ihost_ack := '0';
+
+ icore_txd := core_txd;
+
+ -- keep current command to i2c_core
+ icore_cmd := core_cmd;
+
+ -- no shifting or loading of shift-register
+ ishift := '0';
+ iload := '0';
+
+ -- keep current state;
+ nxt_state := state;
+ case state is
+ when st_idle =>
+ if (go = '1') then
+ if (start = '1') then
+ nxt_state := st_start;
+ icore_cmd := CMD_START;
+ elsif (read = '1') then
+ nxt_state := st_read;
+ icore_cmd := CMD_READ;
+ idcnt := "111";
+ else
+ nxt_state := st_write;
+ icore_cmd := CMD_WRITE;
+ idcnt := "111";
+ iload := '1';
+ end if;
+ end if;
+
+ when st_start =>
+ if (core_ack = '1') then
+ if (read = '1') then
+ nxt_state := st_read;
+ icore_cmd := CMD_READ;
+ idcnt := "111";
+ else
+ nxt_state := st_write;
+ icore_cmd := CMD_WRITE;
+ idcnt := "111";
+ iload := '1';
+ end if;
+ end if;
+
+ when st_write =>
+ if (core_ack = '1') then
+ idcnt := dcnt -1; -- count down Data_counter
+ icore_txd := sr(7);
+ if (dcnt = 0) then
+ nxt_state := st_ack;
+ icore_cmd := CMD_READ;
+ else
+ ishift := '1';
+-- icore_txd := sr(7);
+ end if;
+ end if;
+
+ when st_read =>
+ if (core_ack = '1') then
+ idcnt := dcnt -1; -- count down Data_counter
+ ishift := '1';
+ if (dcnt = 0) then
+ nxt_state := st_ack;
+ icore_cmd := CMD_WRITE;
+ icore_txd := ack_in;
+ end if;
+ end if;
+
+ when st_ack =>
+ if (core_ack = '1') then
+ -- generate command acknowledge signal
+ ihost_ack := '1';
+
+ -- Perform an additional shift, needed for 'read' (store last received bit in shift register)
+ ishift := '1';
+
+ -- check for stop; Should a STOP command be generated ?
+ if (stop = '1') then
+ nxt_state := st_stop;
+ icore_cmd := CMD_STOP;
+ else
+ nxt_state := st_idle;
+ icore_cmd := CMD_NOP;
+ end if;
+ end if;
+
+ when st_stop =>
+ if (core_ack = '1') then
+ nxt_state := st_idle;
+ icore_cmd := CMD_NOP;
+ end if;
+
+ when others => -- illegal states
+ nxt_state := st_idle;
+ icore_cmd := CMD_NOP;
+ end case;
+
+ -- generate registers
+ if (nReset = '0') then
+ core_cmd <= CMD_NOP;
+ core_txd <= '0';
+
+ shift <= '0';
+ ld <= '0';
+
+ dcnt <= "111";
+ host_ack <= '0';
+
+ state <= st_idle;
+ elsif (clk'event and clk = '1') then
+ if (ena = '1') then
+ state <= nxt_state;
+
+ dcnt <= idcnt;
+ shift <= ishift;
+ ld <= iload;
+
+ core_cmd <= icore_cmd;
+ core_txd <= icore_txd;
+
+ host_ack <= ihost_ack;
+ end if;
+ end if;
+ end process nxt_state_decoder;
+
+ end block statemachine;
+
+end architecture structural;
+
+
+--
+--
+-- I2C Core
+--
+-- Translate simple commands into SCL/SDA transitions
+-- Each command has 5 states, A/B/C/D/idle
+--
+-- start: SCL ~~~~~~~~~~\____
+-- SDA ~~~~~~~~\______
+-- x | A | B | C | D | i
+--
+-- repstart SCL ____/~~~~\___
+-- SDA __/~~~\______
+-- x | A | B | C | D | i
+--
+-- stop SCL ____/~~~~~~~~
+-- SDA ==\____/~~~~~
+-- x | A | B | C | D | i
+--
+--- write SCL ____/~~~~\____
+-- SDA ==X=========X=
+-- x | A | B | C | D | i
+--
+--- read SCL ____/~~~~\____
+-- SDA XXXX=====XXXX
+-- x | A | B | C | D | i
+--
+
+-- Timing: Normal mode Fast mode
+-----------------------------------------------------------------
+-- Fscl 100KHz 400KHz
+-- Th_scl 4.0us 0.6us High period of SCL
+-- Tl_scl 4.7us 1.3us Low period of SCL
+-- Tsu:sta 4.7us 0.6us setup time for a repeated start condition
+-- Tsu:sto 4.0us 0.6us setup time for a stop conditon
+-- Tbuf 4.7us 1.3us Bus free time between a stop and start condition
+--
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+entity i2c_core is
+ port (
+ clk : in std_logic;
+ nReset : in std_logic;
+
+ clk_cnt : in unsigned(7 downto 0);
+
+ cmd : in std_logic_vector(2 downto 0);
+ cmd_ack : out std_logic;
+ busy : out std_logic;
+
+ Din : in std_logic;
+ Dout : out std_logic;
+
+ SCL : inout std_logic;
+ SDA : inout std_logic
+ );
+end entity i2c_core;
+
+architecture structural of i2c_core is
+ constant CMD_NOP : std_logic_vector(2 downto 0) := "000";
+ constant CMD_START : std_logic_vector(2 downto 0) := "010";
+ constant CMD_STOP : std_logic_vector(2 downto 0) := "011";
+ constant CMD_READ : std_logic_vector(2 downto 0) := "100";
+ constant CMD_WRITE : std_logic_vector(2 downto 0) := "101";
+
+ type cmds is (idle, start_a, start_b, start_c, start_d, stop_a, stop_b, stop_c, rd_a, rd_b, rd_c, rd_d, wr_a, wr_b, wr_c, wr_d);
+ signal state : cmds;
+ signal SDAo, SCLo : std_logic;
+ signal txd : std_logic;
+ signal clk_en, slave_wait :std_logic;
+ signal cnt : unsigned(7 downto 0) := clk_cnt;
+begin
+ -- whenever the slave is not ready it can delay the cycle by pulling SCL low
+ slave_wait <= '1' when ((SCLo = '1') and (SCL = '0')) else '0';
+
+ -- generate clk enable signal
+ gen_clken: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ cnt <= (others => '0');
+ clk_en <= '1'; --'0';
+ elsif (clk'event and clk = '1') then
+ if (cnt = 0) then
+ clk_en <= '1';
+ cnt <= clk_cnt;
+ else
+ if (slave_wait = '0') then
+ cnt <= cnt -1;
+ end if;
+ clk_en <= '0';
+ end if;
+ end if;
+ end process gen_clken;
+
+ -- generate statemachine
+ nxt_state_decoder : process (clk, nReset, state, cmd, SDA)
+ variable nxt_state : cmds;
+ variable icmd_ack, ibusy, store_sda : std_logic;
+ variable itxd : std_logic;
+ begin
+
+ nxt_state := state;
+
+ icmd_ack := '0'; -- default no acknowledge
+ ibusy := '1'; -- default busy
+
+ store_sda := '0';
+
+ itxd := txd;
+
+ case (state) is
+ -- idle
+ when idle =>
+ case cmd is
+ when CMD_START =>
+ nxt_state := start_a;
+ icmd_ack := '1'; -- command completed
+
+ when CMD_STOP =>
+ nxt_state := stop_a;
+ icmd_ack := '1'; -- command completed
+
+ when CMD_WRITE =>
+ nxt_state := wr_a;
+ icmd_ack := '1'; -- command completed
+ itxd := Din;
+
+ when CMD_READ =>
+ nxt_state := rd_a;
+ icmd_ack := '1'; -- command completed
+
+ when others =>
+ nxt_state := idle;
+-- don't acknowledge NOP command icmd_ack := '1'; -- command completed
+ ibusy := '0';
+ end case;
+
+ -- start
+ when start_a =>
+ nxt_state := start_b;
+
+ when start_b =>
+ nxt_state := start_c;
+
+ when start_c =>
+ nxt_state := start_d;
+
+ when start_d =>
+ nxt_state := idle;
+ ibusy := '0'; -- not busy when idle
+
+
+ -- stop
+ when stop_a =>
+ nxt_state := stop_b;
+
+ when stop_b =>
+ nxt_state := stop_c;
+
+ when stop_c =>
+-- nxt_state := stop_d;
+
+-- when stop_d =>
+ nxt_state := idle;
+ ibusy := '0'; -- not busy when idle
+
+ -- read
+ when rd_a =>
+ nxt_state := rd_b;
+
+ when rd_b =>
+ nxt_state := rd_c;
+
+ when rd_c =>
+ nxt_state := rd_d;
+ store_sda := '1';
+
+ when rd_d =>
+ nxt_state := idle;
+ ibusy := '0'; -- not busy when idle
+
+ -- write
+ when wr_a =>
+ nxt_state := wr_b;
+
+ when wr_b =>
+ nxt_state := wr_c;
+
+ when wr_c =>
+ nxt_state := wr_d;
+
+ when wr_d =>
+ nxt_state := idle;
+ ibusy := '0'; -- not busy when idle
+
+ end case;
+
+ -- generate regs
+ if (nReset = '0') then
+ state <= idle;
+ cmd_ack <= '0';
+ busy <= '0';
+ txd <= '0';
+ Dout <= '0';
+ elsif (clk'event and clk = '1') then
+ if (clk_en = '1') then
+ state <= nxt_state;
+ busy <= ibusy;
+
+ txd <= itxd;
+ if (store_sda = '1') then
+ Dout <= SDA;
+ end if;
+ end if;
+
+ cmd_ack <= icmd_ack and clk_en;
+ end if;
+ end process nxt_state_decoder;
+
+ --
+ -- convert states to SCL and SDA signals
+ --
+ output_decoder: process (clk, nReset, state)
+ variable iscl, isda : std_logic;
+ begin
+ case (state) is
+ when idle =>
+ iscl := SCLo; -- keep SCL in same state
+ isda := SDA; -- keep SDA in same state
+
+ -- start
+ when start_a =>
+ iscl := SCLo; -- keep SCL in same state (for repeated start)
+ isda := '1'; -- set SDA high
+
+ when start_b =>
+ iscl := '1'; -- set SCL high
+ isda := '1'; -- keep SDA high
+
+ when start_c =>
+ iscl := '1'; -- keep SCL high
+ isda := '0'; -- sel SDA low
+
+ when start_d =>
+ iscl := '0'; -- set SCL low
+ isda := '0'; -- keep SDA low
+
+ -- stop
+ when stop_a =>
+ iscl := '0'; -- keep SCL disabled
+ isda := '0'; -- set SDA low
+
+ when stop_b =>
+ iscl := '1'; -- set SCL high
+ isda := '0'; -- keep SDA low
+
+ when stop_c =>
+ iscl := '1'; -- keep SCL high
+ isda := '1'; -- set SDA high
+
+ -- write
+ when wr_a =>
+ iscl := '0'; -- keep SCL low
+-- isda := txd; -- set SDA
+ isda := Din;
+
+ when wr_b =>
+ iscl := '1'; -- set SCL high
+-- isda := txd; -- set SDA
+ isda := Din;
+
+ when wr_c =>
+ iscl := '1'; -- keep SCL high
+-- isda := txd; -- set SDA
+ isda := Din;
+
+ when wr_d =>
+ iscl := '0'; -- set SCL low
+-- isda := txd; -- set SDA
+ isda := Din;
+
+ -- read
+ when rd_a =>
+ iscl := '0'; -- keep SCL low
+ isda := '1'; -- tri-state SDA
+
+ when rd_b =>
+ iscl := '1'; -- set SCL high
+ isda := '1'; -- tri-state SDA
+
+ when rd_c =>
+ iscl := '1'; -- keep SCL high
+ isda := '1'; -- tri-state SDA
+
+ when rd_d =>
+ iscl := '0'; -- set SCL low
+ isda := '1'; -- tri-state SDA
+ end case;
+
+ -- generate registers
+ if (nReset = '0') then
+ SCLo <= '1';
+ SDAo <= '1';
+ elsif (clk'event and clk = '1') then
+ if (clk_en = '1') then
+ SCLo <= iscl;
+ SDAo <= isda;
+ end if;
+ end if;
+ end process output_decoder;
+
+ SCL <= '0' when (SCLo = '0') else 'Z'; -- since SCL is externally pulled-up convert a '1' to a 'Z'(tri-state)
+ SDA <= '0' when (SDAo = '0') else 'Z'; -- since SDA is externally pulled-up convert a '1' to a 'Z'(tri-state)
+-- SCL <= SCLo;
+-- SDA <= SDAo;
+
+end architecture structural;
+
+
+
+
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd
new file mode 100644
index 000000000..1b8eb96d2
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd
@@ -0,0 +1,495 @@
+---------------------------------------------------------------------
+---- ----
+---- WISHBONE revB2 I2C Master Core; bit-controller ----
+---- ----
+---- ----
+---- Author: Richard Herveille ----
+---- richard@asics.ws ----
+---- www.asics.ws ----
+---- ----
+---- Downloaded from: http://www.opencores.org/projects/i2c/ ----
+---- ----
+---------------------------------------------------------------------
+---- ----
+---- Copyright (C) 2000 Richard Herveille ----
+---- richard@asics.ws ----
+---- ----
+---- This source file may be used and distributed without ----
+---- restriction provided that this copyright statement is not ----
+---- removed from the file and that any derivative work contains ----
+---- the original copyright notice and the associated disclaimer.----
+---- ----
+---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
+---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
+---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
+---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
+---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
+---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
+---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
+---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
+---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
+---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
+---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
+---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
+---- POSSIBILITY OF SUCH DAMAGE. ----
+---- ----
+---------------------------------------------------------------------
+
+-- CVS Log
+--
+-- $Id: i2c_master_bit_ctrl.vhd,v 1.14 2006/10/11 12:10:13 rherveille Exp $
+--
+-- $Date: 2006/10/11 12:10:13 $
+-- $Revision: 1.14 $
+-- $Author: rherveille $
+-- $Locker: $
+-- $State: Exp $
+--
+-- Change History:
+-- $Log: i2c_master_bit_ctrl.vhd,v $
+-- Revision 1.14 2006/10/11 12:10:13 rherveille
+-- Added missing semicolons ';' on endif
+--
+-- Revision 1.13 2006/10/06 10:48:24 rherveille
+-- fixed short scl high pulse after clock stretch
+--
+-- Revision 1.12 2004/05/07 11:53:31 rherveille
+-- Fixed previous fix :) Made a variable vs signal mistake.
+--
+-- Revision 1.11 2004/05/07 11:04:00 rherveille
+-- Fixed a bug where the core would signal an arbitration lost (AL bit set), when another master controls the bus and the other master generates a STOP bit.
+--
+-- Revision 1.10 2004/02/27 07:49:43 rherveille
+-- Fixed a bug in the arbitration-lost signal generation. VHDL version only.
+--
+-- Revision 1.9 2003/08/12 14:48:37 rherveille
+-- Forgot an 'end if' :-/
+--
+-- Revision 1.8 2003/08/09 07:01:13 rherveille
+-- Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
+-- Fixed a potential bug in the byte controller's host-acknowledge generation.
+--
+-- Revision 1.7 2003/02/05 00:06:02 rherveille
+-- Fixed a bug where the core would trigger an erroneous 'arbitration lost' interrupt after being reset, when the reset pulse width < 3 clk cycles.
+--
+-- Revision 1.6 2003/02/01 02:03:06 rherveille
+-- Fixed a few 'arbitration lost' bugs. VHDL version only.
+--
+-- Revision 1.5 2002/12/26 16:05:47 rherveille
+-- Core is now a Multimaster I2C controller.
+--
+-- Revision 1.4 2002/11/30 22:24:37 rherveille
+-- Cleaned up code
+--
+-- Revision 1.3 2002/10/30 18:09:53 rherveille
+-- Fixed some reported minor start/stop generation timing issuess.
+--
+-- Revision 1.2 2002/06/15 07:37:04 rherveille
+-- Fixed a small timing bug in the bit controller.\nAdded verilog simulation environment.
+--
+-- Revision 1.1 2001/11/05 12:02:33 rherveille
+-- Split i2c_master_core.vhd into separate files for each entity; same layout as verilog version.
+-- Code updated, is now up-to-date to doc. rev.0.4.
+-- Added headers.
+--
+
+
+--
+-------------------------------------
+-- Bit controller section
+------------------------------------
+--
+-- Translate simple commands into SCL/SDA transitions
+-- Each command has 5 states, A/B/C/D/idle
+--
+-- start: SCL ~~~~~~~~~~~~~~\____
+-- SDA XX/~~~~~~~\______
+-- x | A | B | C | D | i
+--
+-- repstart SCL ______/~~~~~~~\___
+-- SDA __/~~~~~~~\______
+-- x | A | B | C | D | i
+--
+-- stop SCL _______/~~~~~~~~~~~
+-- SDA ==\___________/~~~~~
+-- x | A | B | C | D | i
+--
+--- write SCL ______/~~~~~~~\____
+-- SDA XXX===============XX
+-- x | A | B | C | D | i
+--
+--- read SCL ______/~~~~~~~\____
+-- SDA XXXXXXX=XXXXXXXXXXX
+-- x | A | B | C | D | i
+--
+
+-- Timing: Normal mode Fast mode
+-----------------------------------------------------------------
+-- Fscl 100KHz 400KHz
+-- Th_scl 4.0us 0.6us High period of SCL
+-- Tl_scl 4.7us 1.3us Low period of SCL
+-- Tsu:sta 4.7us 0.6us setup time for a repeated start condition
+-- Tsu:sto 4.0us 0.6us setup time for a stop conditon
+-- Tbuf 4.7us 1.3us Bus free time between a stop and start condition
+--
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+entity i2c_master_bit_ctrl is
+ port (
+ clk : in std_logic;
+ rst : in std_logic;
+ nReset : in std_logic;
+ ena : in std_logic; -- core enable signal
+
+ clk_cnt : in unsigned(15 downto 0); -- clock prescale value
+
+ cmd : in std_logic_vector(3 downto 0);
+ cmd_ack : out std_logic; -- command completed
+ busy : out std_logic; -- i2c bus busy
+ al : out std_logic; -- arbitration lost
+
+ din : in std_logic;
+ dout : out std_logic;
+
+ -- i2c lines
+ scl_i : in std_logic; -- i2c clock line input
+ scl_o : out std_logic; -- i2c clock line output
+ scl_oen : out std_logic; -- i2c clock line output enable, active low
+ sda_i : in std_logic; -- i2c data line input
+ sda_o : out std_logic; -- i2c data line output
+ sda_oen : out std_logic -- i2c data line output enable, active low
+ );
+end entity i2c_master_bit_ctrl;
+
+architecture structural of i2c_master_bit_ctrl is
+ constant I2C_CMD_NOP : std_logic_vector(3 downto 0) := "0000";
+ constant I2C_CMD_START : std_logic_vector(3 downto 0) := "0001";
+ constant I2C_CMD_STOP : std_logic_vector(3 downto 0) := "0010";
+ constant I2C_CMD_READ : std_logic_vector(3 downto 0) := "0100";
+ constant I2C_CMD_WRITE : std_logic_vector(3 downto 0) := "1000";
+
+ type states is (idle, start_a, start_b, start_c, start_d, start_e,
+ stop_a, stop_b, stop_c, stop_d, rd_a, rd_b, rd_c, rd_d, wr_a, wr_b, wr_c, wr_d);
+ signal c_state : states;
+
+ signal iscl_oen, isda_oen : std_logic; -- internal I2C lines
+ signal sda_chk : std_logic; -- check SDA status (multi-master arbitration)
+ signal dscl_oen : std_logic; -- delayed scl_oen signals
+ signal sSCL, sSDA : std_logic; -- synchronized SCL and SDA inputs
+ signal clk_en, slave_wait : std_logic; -- clock generation signals
+ signal ial : std_logic; -- internal arbitration lost signal
+-- signal cnt : unsigned(15 downto 0) := clk_cnt; -- clock divider counter (simulation)
+ signal cnt : unsigned(15 downto 0); -- clock divider counter (synthesis)
+
+begin
+ -- whenever the slave is not ready it can delay the cycle by pulling SCL low
+ -- delay scl_oen
+ process (clk)
+ begin
+ if (clk'event and clk = '1') then
+ dscl_oen <= iscl_oen;
+ end if;
+ end process;
+ slave_wait <= dscl_oen and not sSCL;
+
+ -- generate clk enable signal
+ gen_clken: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ cnt <= (others => '0');
+ clk_en <= '1';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ cnt <= (others => '0');
+ clk_en <= '1';
+ elsif ( (cnt = 0) or (ena = '0') ) then
+ cnt <= clk_cnt;
+ clk_en <= '1';
+ elsif (slave_wait = '1') then
+ cnt <= cnt;
+ clk_en <= '0';
+ else
+ cnt <= cnt -1;
+ clk_en <= '0';
+ end if;
+ end if;
+ end process gen_clken;
+
+
+ -- generate bus status controller
+ bus_status_ctrl: block
+ signal dSCL, dSDA : std_logic; -- delayes sSCL and sSDA
+ signal sta_condition : std_logic; -- start detected
+ signal sto_condition : std_logic; -- stop detected
+ signal cmd_stop : std_logic; -- STOP command
+ signal ibusy : std_logic; -- internal busy signal
+ begin
+ -- synchronize SCL and SDA inputs
+ synch_scl_sda: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ sSCL <= '1';
+ sSDA <= '1';
+
+ dSCL <= '1';
+ dSDA <= '1';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ sSCL <= '1';
+ sSDA <= '1';
+
+ dSCL <= '1';
+ dSDA <= '1';
+ else
+ sSCL <= scl_i;
+ sSDA <= sda_i;
+
+ dSCL <= sSCL;
+ dSDA <= sSDA;
+ end if;
+ end if;
+ end process synch_SCL_SDA;
+
+ -- detect start condition => detect falling edge on SDA while SCL is high
+ -- detect stop condition => detect rising edge on SDA while SCL is high
+ detect_sta_sto: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ sta_condition <= '0';
+ sto_condition <= '0';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ sta_condition <= '0';
+ sto_condition <= '0';
+ else
+ sta_condition <= (not sSDA and dSDA) and sSCL;
+ sto_condition <= (sSDA and not dSDA) and sSCL;
+ end if;
+ end if;
+ end process detect_sta_sto;
+
+ -- generate i2c-bus busy signal
+ gen_busy: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ ibusy <= '0';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ ibusy <= '0';
+ else
+ ibusy <= (sta_condition or ibusy) and not sto_condition;
+ end if;
+ end if;
+ end process gen_busy;
+ busy <= ibusy;
+
+
+ -- generate arbitration lost signal
+ -- aribitration lost when:
+ -- 1) master drives SDA high, but the i2c bus is low
+ -- 2) stop detected while not requested (detect during 'idle' state)
+ gen_al: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ cmd_stop <= '0';
+ ial <= '0';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ cmd_stop <= '0';
+ ial <= '0';
+ else
+ if (clk_en = '1') then
+ if (cmd = I2C_CMD_STOP) then
+ cmd_stop <= '1';
+ else
+ cmd_stop <= '0';
+ end if;
+ end if;
+
+ if (c_state = idle) then
+ ial <= (sda_chk and not sSDA and isda_oen);
+ else
+ ial <= (sda_chk and not sSDA and isda_oen) or (sto_condition and not cmd_stop);
+ end if;
+
+ end if;
+ end if;
+ end process gen_al;
+ al <= ial;
+
+ -- generate dout signal, store dout on rising edge of SCL
+ gen_dout: process(clk)
+ begin
+ if (clk'event and clk = '1') then
+ if (sSCL = '1' and dSCL = '0') then
+ dout <= sSDA;
+ end if;
+ end if;
+ end process gen_dout;
+ end block bus_status_ctrl;
+
+
+ -- generate statemachine
+ nxt_state_decoder : process (clk, nReset, c_state, cmd)
+ begin
+ if (nReset = '0') then
+ c_state <= idle;
+ cmd_ack <= '0';
+ iscl_oen <= '1';
+ isda_oen <= '1';
+ sda_chk <= '0';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1' or ial = '1') then
+ c_state <= idle;
+ cmd_ack <= '0';
+ iscl_oen <= '1';
+ isda_oen <= '1';
+ sda_chk <= '0';
+ else
+ cmd_ack <= '0'; -- default no acknowledge
+
+ if (clk_en = '1') then
+ case (c_state) is
+ -- idle
+ when idle =>
+ case cmd is
+ when I2C_CMD_START => c_state <= start_a;
+ when I2C_CMD_STOP => c_state <= stop_a;
+ when I2C_CMD_WRITE => c_state <= wr_a;
+ when I2C_CMD_READ => c_state <= rd_a;
+ when others => c_state <= idle; -- NOP command
+ end case;
+
+ iscl_oen <= iscl_oen; -- keep SCL in same state
+ isda_oen <= isda_oen; -- keep SDA in same state
+ sda_chk <= '0'; -- don't check SDA
+
+ -- start
+ when start_a =>
+ c_state <= start_b;
+ iscl_oen <= iscl_oen; -- keep SCL in same state (for repeated start)
+ isda_oen <= '1'; -- set SDA high
+ sda_chk <= '0'; -- don't check SDA
+
+ when start_b =>
+ c_state <= start_c;
+ iscl_oen <= '1'; -- set SCL high
+ isda_oen <= '1'; -- keep SDA high
+ sda_chk <= '0'; -- don't check SDA
+
+ when start_c =>
+ c_state <= start_d;
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= '0'; -- set SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ when start_d =>
+ c_state <= start_e;
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= '0'; -- keep SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ when start_e =>
+ c_state <= idle;
+ cmd_ack <= '1'; -- command completed
+ iscl_oen <= '0'; -- set SCL low
+ isda_oen <= '0'; -- keep SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ -- stop
+ when stop_a =>
+ c_state <= stop_b;
+ iscl_oen <= '0'; -- keep SCL low
+ isda_oen <= '0'; -- set SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ when stop_b =>
+ c_state <= stop_c;
+ iscl_oen <= '1'; -- set SCL high
+ isda_oen <= '0'; -- keep SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ when stop_c =>
+ c_state <= stop_d;
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= '0'; -- keep SDA low
+ sda_chk <= '0'; -- don't check SDA
+
+ when stop_d =>
+ c_state <= idle;
+ cmd_ack <= '1'; -- command completed
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= '1'; -- set SDA high
+ sda_chk <= '0'; -- don't check SDA
+
+ -- read
+ when rd_a =>
+ c_state <= rd_b;
+ iscl_oen <= '0'; -- keep SCL low
+ isda_oen <= '1'; -- tri-state SDA
+ sda_chk <= '0'; -- don't check SDA
+
+ when rd_b =>
+ c_state <= rd_c;
+ iscl_oen <= '1'; -- set SCL high
+ isda_oen <= '1'; -- tri-state SDA
+ sda_chk <= '0'; -- don't check SDA
+
+ when rd_c =>
+ c_state <= rd_d;
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= '1'; -- tri-state SDA
+ sda_chk <= '0'; -- don't check SDA
+
+ when rd_d =>
+ c_state <= idle;
+ cmd_ack <= '1'; -- command completed
+ iscl_oen <= '0'; -- set SCL low
+ isda_oen <= '1'; -- tri-state SDA
+ sda_chk <= '0'; -- don't check SDA
+
+ -- write
+ when wr_a =>
+ c_state <= wr_b;
+ iscl_oen <= '0'; -- keep SCL low
+ isda_oen <= din; -- set SDA
+ sda_chk <= '0'; -- don't check SDA (SCL low)
+
+ when wr_b =>
+ c_state <= wr_c;
+ iscl_oen <= '1'; -- set SCL high
+ isda_oen <= din; -- keep SDA
+ sda_chk <= '1'; -- check SDA
+
+ when wr_c =>
+ c_state <= wr_d;
+ iscl_oen <= '1'; -- keep SCL high
+ isda_oen <= din; -- keep SDA
+ sda_chk <= '1'; -- check SDA
+
+ when wr_d =>
+ c_state <= idle;
+ cmd_ack <= '1'; -- command completed
+ iscl_oen <= '0'; -- set SCL low
+ isda_oen <= din; -- keep SDA
+ sda_chk <= '0'; -- don't check SDA (SCL low)
+
+ when others =>
+
+ end case;
+ end if;
+ end if;
+ end if;
+ end process nxt_state_decoder;
+
+
+ -- assign outputs
+ scl_o <= '0';
+ scl_oen <= iscl_oen;
+ sda_o <= '0';
+ sda_oen <= isda_oen;
+end architecture structural;
+
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd
new file mode 100644
index 000000000..bdb2a881e
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd
@@ -0,0 +1,370 @@
+---------------------------------------------------------------------
+---- ----
+---- WISHBONE revB2 compl. I2C Master Core; byte-controller ----
+---- ----
+---- ----
+---- Author: Richard Herveille ----
+---- richard@asics.ws ----
+---- www.asics.ws ----
+---- ----
+---- Downloaded from: http://www.opencores.org/projects/i2c/ ----
+---- ----
+---------------------------------------------------------------------
+---- ----
+---- Copyright (C) 2000 Richard Herveille ----
+---- richard@asics.ws ----
+---- ----
+---- This source file may be used and distributed without ----
+---- restriction provided that this copyright statement is not ----
+---- removed from the file and that any derivative work contains ----
+---- the original copyright notice and the associated disclaimer.----
+---- ----
+---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
+---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
+---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
+---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
+---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
+---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
+---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
+---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
+---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
+---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
+---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
+---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
+---- POSSIBILITY OF SUCH DAMAGE. ----
+---- ----
+---------------------------------------------------------------------
+
+-- CVS Log
+--
+-- $Id: i2c_master_byte_ctrl.vhd,v 1.5 2004/02/18 11:41:48 rherveille Exp $
+--
+-- $Date: 2004/02/18 11:41:48 $
+-- $Revision: 1.5 $
+-- $Author: rherveille $
+-- $Locker: $
+-- $State: Exp $
+--
+-- Change History:
+-- $Log: i2c_master_byte_ctrl.vhd,v $
+-- Revision 1.5 2004/02/18 11:41:48 rherveille
+-- Fixed a potential bug in the statemachine. During a 'stop' 2 cmd_ack signals were generated. Possibly canceling a new start command.
+--
+-- Revision 1.4 2003/08/09 07:01:13 rherveille
+-- Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
+-- Fixed a potential bug in the byte controller's host-acknowledge generation.
+--
+-- Revision 1.3 2002/12/26 16:05:47 rherveille
+-- Core is now a Multimaster I2C controller.
+--
+-- Revision 1.2 2002/11/30 22:24:37 rherveille
+-- Cleaned up code
+--
+-- Revision 1.1 2001/11/05 12:02:33 rherveille
+-- Split i2c_master_core.vhd into separate files for each entity; same layout as verilog version.
+-- Code updated, is now up-to-date to doc. rev.0.4.
+-- Added headers.
+--
+
+
+
+
+--
+------------------------------------------
+-- Byte controller section
+------------------------------------------
+--
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+entity i2c_master_byte_ctrl is
+ port (
+ clk : in std_logic;
+ rst : in std_logic; -- synchronous active high reset (WISHBONE compatible)
+ nReset : in std_logic; -- asynchornous active low reset (FPGA compatible)
+ ena : in std_logic; -- core enable signal
+
+ clk_cnt : in unsigned(15 downto 0); -- 4x SCL
+
+ -- input signals
+ start,
+ stop,
+ read,
+ write,
+ ack_in : std_logic;
+ din : in std_logic_vector(7 downto 0);
+
+ -- output signals
+ cmd_ack : out std_logic; -- command done
+ ack_out : out std_logic;
+ i2c_busy : out std_logic; -- arbitration lost
+ i2c_al : out std_logic; -- i2c bus busy
+ dout : out std_logic_vector(7 downto 0);
+
+ -- i2c lines
+ scl_i : in std_logic; -- i2c clock line input
+ scl_o : out std_logic; -- i2c clock line output
+ scl_oen : out std_logic; -- i2c clock line output enable, active low
+ sda_i : in std_logic; -- i2c data line input
+ sda_o : out std_logic; -- i2c data line output
+ sda_oen : out std_logic -- i2c data line output enable, active low
+ );
+end entity i2c_master_byte_ctrl;
+
+architecture structural of i2c_master_byte_ctrl is
+ component i2c_master_bit_ctrl is
+ port (
+ clk : in std_logic;
+ rst : in std_logic;
+ nReset : in std_logic;
+ ena : in std_logic; -- core enable signal
+
+ clk_cnt : in unsigned(15 downto 0); -- clock prescale value
+
+ cmd : in std_logic_vector(3 downto 0);
+ cmd_ack : out std_logic; -- command done
+ busy : out std_logic; -- i2c bus busy
+ al : out std_logic; -- arbitration lost
+
+ din : in std_logic;
+ dout : out std_logic;
+
+ -- i2c lines
+ scl_i : in std_logic; -- i2c clock line input
+ scl_o : out std_logic; -- i2c clock line output
+ scl_oen : out std_logic; -- i2c clock line output enable, active low
+ sda_i : in std_logic; -- i2c data line input
+ sda_o : out std_logic; -- i2c data line output
+ sda_oen : out std_logic -- i2c data line output enable, active low
+ );
+ end component i2c_master_bit_ctrl;
+
+ -- commands for bit_controller block
+ constant I2C_CMD_NOP : std_logic_vector(3 downto 0) := "0000";
+ constant I2C_CMD_START : std_logic_vector(3 downto 0) := "0001";
+ constant I2C_CMD_STOP : std_logic_vector(3 downto 0) := "0010";
+ constant I2C_CMD_READ : std_logic_vector(3 downto 0) := "0100";
+ constant I2C_CMD_WRITE : std_logic_vector(3 downto 0) := "1000";
+
+ -- signals for bit_controller
+ signal core_cmd : std_logic_vector(3 downto 0);
+ signal core_ack, core_txd, core_rxd : std_logic;
+ signal al : std_logic;
+
+ -- signals for shift register
+ signal sr : std_logic_vector(7 downto 0); -- 8bit shift register
+ signal shift, ld : std_logic;
+
+ -- signals for state machine
+ signal go, host_ack : std_logic;
+ signal dcnt : unsigned(2 downto 0); -- data counter
+ signal cnt_done : std_logic;
+
+begin
+ -- hookup bit_controller
+ bit_ctrl: i2c_master_bit_ctrl port map(
+ clk => clk,
+ rst => rst,
+ nReset => nReset,
+ ena => ena,
+ clk_cnt => clk_cnt,
+ cmd => core_cmd,
+ cmd_ack => core_ack,
+ busy => i2c_busy,
+ al => al,
+ din => core_txd,
+ dout => core_rxd,
+ scl_i => scl_i,
+ scl_o => scl_o,
+ scl_oen => scl_oen,
+ sda_i => sda_i,
+ sda_o => sda_o,
+ sda_oen => sda_oen
+ );
+ i2c_al <= al;
+
+ -- generate host-command-acknowledge
+ cmd_ack <= host_ack;
+
+ -- generate go-signal
+ go <= (read or write or stop) and not host_ack;
+
+ -- assign Dout output to shift-register
+ dout <= sr;
+
+ -- generate shift register
+ shift_register: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ sr <= (others => '0');
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ sr <= (others => '0');
+ elsif (ld = '1') then
+ sr <= din;
+ elsif (shift = '1') then
+ sr <= (sr(6 downto 0) & core_rxd);
+ end if;
+ end if;
+ end process shift_register;
+
+ -- generate data-counter
+ data_cnt: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ dcnt <= (others => '0');
+ elsif (clk'event and clk = '1') then
+ if (rst = '1') then
+ dcnt <= (others => '0');
+ elsif (ld = '1') then
+ dcnt <= (others => '1'); -- load counter with 7
+ elsif (shift = '1') then
+ dcnt <= dcnt -1;
+ end if;
+ end if;
+ end process data_cnt;
+
+ cnt_done <= '1' when (dcnt = 0) else '0';
+
+ --
+ -- state machine
+ --
+ statemachine : block
+ type states is (st_idle, st_start, st_read, st_write, st_ack, st_stop);
+ signal c_state : states;
+ begin
+ --
+ -- command interpreter, translate complex commands into simpler I2C commands
+ --
+ nxt_state_decoder: process(clk, nReset)
+ begin
+ if (nReset = '0') then
+ core_cmd <= I2C_CMD_NOP;
+ core_txd <= '0';
+ shift <= '0';
+ ld <= '0';
+ host_ack <= '0';
+ c_state <= st_idle;
+ ack_out <= '0';
+ elsif (clk'event and clk = '1') then
+ if (rst = '1' or al = '1') then
+ core_cmd <= I2C_CMD_NOP;
+ core_txd <= '0';
+ shift <= '0';
+ ld <= '0';
+ host_ack <= '0';
+ c_state <= st_idle;
+ ack_out <= '0';
+ else
+ -- initialy reset all signal
+ core_txd <= sr(7);
+ shift <= '0';
+ ld <= '0';
+ host_ack <= '0';
+
+ case c_state is
+ when st_idle =>
+ if (go = '1') then
+ if (start = '1') then
+ c_state <= st_start;
+ core_cmd <= I2C_CMD_START;
+ elsif (read = '1') then
+ c_state <= st_read;
+ core_cmd <= I2C_CMD_READ;
+ elsif (write = '1') then
+ c_state <= st_write;
+ core_cmd <= I2C_CMD_WRITE;
+ else -- stop
+ c_state <= st_stop;
+ core_cmd <= I2C_CMD_STOP;
+ end if;
+
+ ld <= '1';
+ end if;
+
+ when st_start =>
+ if (core_ack = '1') then
+ if (read = '1') then
+ c_state <= st_read;
+ core_cmd <= I2C_CMD_READ;
+ else
+ c_state <= st_write;
+ core_cmd <= I2C_CMD_WRITE;
+ end if;
+
+ ld <= '1';
+ end if;
+
+ when st_write =>
+ if (core_ack = '1') then
+ if (cnt_done = '1') then
+ c_state <= st_ack;
+ core_cmd <= I2C_CMD_READ;
+ else
+ c_state <= st_write; -- stay in same state
+ core_cmd <= I2C_CMD_WRITE; -- write next bit
+ shift <= '1';
+ end if;
+ end if;
+
+ when st_read =>
+ if (core_ack = '1') then
+ if (cnt_done = '1') then
+ c_state <= st_ack;
+ core_cmd <= I2C_CMD_WRITE;
+ else
+ c_state <= st_read; -- stay in same state
+ core_cmd <= I2C_CMD_READ; -- read next bit
+ end if;
+
+ shift <= '1';
+ core_txd <= ack_in;
+ end if;
+
+ when st_ack =>
+ if (core_ack = '1') then
+ -- check for stop; Should a STOP command be generated ?
+ if (stop = '1') then
+ c_state <= st_stop;
+ core_cmd <= I2C_CMD_STOP;
+ else
+ c_state <= st_idle;
+ core_cmd <= I2C_CMD_NOP;
+
+ -- generate command acknowledge signal
+ host_ack <= '1';
+ end if;
+
+ -- assign ack_out output to core_rxd (contains last received bit)
+ ack_out <= core_rxd;
+
+ core_txd <= '1';
+ else
+ core_txd <= ack_in;
+ end if;
+
+ when st_stop =>
+ if (core_ack = '1') then
+ c_state <= st_idle;
+ core_cmd <= I2C_CMD_NOP;
+
+ -- generate command acknowledge signal
+ host_ack <= '1';
+ end if;
+
+ when others => -- illegal states
+ c_state <= st_idle;
+ core_cmd <= I2C_CMD_NOP;
+ report ("Byte controller entered illegal state.");
+
+ end case;
+
+ end if;
+ end if;
+ end process nxt_state_decoder;
+
+ end block statemachine;
+
+end architecture structural;
+
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_top.vhd b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_top.vhd
new file mode 100644
index 000000000..a2557120f
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_top.vhd
@@ -0,0 +1,359 @@
+---------------------------------------------------------------------
+---- ----
+---- WISHBONE revB2 compl. I2C Master Core; top level ----
+---- ----
+---- ----
+---- Author: Richard Herveille ----
+---- richard@asics.ws ----
+---- www.asics.ws ----
+---- ----
+---- Downloaded from: http://www.opencores.org/projects/i2c/ ----
+---- ----
+---------------------------------------------------------------------
+---- ----
+---- Copyright (C) 2000 Richard Herveille ----
+---- richard@asics.ws ----
+---- ----
+---- This source file may be used and distributed without ----
+---- restriction provided that this copyright statement is not ----
+---- removed from the file and that any derivative work contains ----
+---- the original copyright notice and the associated disclaimer.----
+---- ----
+---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
+---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
+---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
+---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
+---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
+---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
+---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
+---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
+---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
+---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
+---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
+---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
+---- POSSIBILITY OF SUCH DAMAGE. ----
+---- ----
+---------------------------------------------------------------------
+
+-- CVS Log
+--
+-- $Id: i2c_master_top.vhd,v 1.7 2004/03/14 10:17:03 rherveille Exp $
+--
+-- $Date: 2004/03/14 10:17:03 $
+-- $Revision: 1.7 $
+-- $Author: rherveille $
+-- $Locker: $
+-- $State: Exp $
+--
+-- Change History:
+-- $Log: i2c_master_top.vhd,v $
+-- Revision 1.7 2004/03/14 10:17:03 rherveille
+-- Fixed simulation issue when writing to CR register
+--
+-- Revision 1.6 2003/08/09 07:01:13 rherveille
+-- Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.
+-- Fixed a potential bug in the byte controller's host-acknowledge generation.
+--
+-- Revision 1.5 2003/02/01 02:03:06 rherveille
+-- Fixed a few 'arbitration lost' bugs. VHDL version only.
+--
+-- Revision 1.4 2002/12/26 16:05:47 rherveille
+-- Core is now a Multimaster I2C controller.
+--
+-- Revision 1.3 2002/11/30 22:24:37 rherveille
+-- Cleaned up code
+--
+-- Revision 1.2 2001/11/10 10:52:44 rherveille
+-- Changed PRER reset value from 0x0000 to 0xffff, conform specs.
+--
+
+
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+entity i2c_master_top is
+ generic(
+ ARST_LVL : std_logic := '0' -- asynchronous reset level
+ );
+ port (
+ -- wishbone signals
+ wb_clk_i : in std_logic; -- master clock input
+ wb_rst_i : in std_logic := '0'; -- synchronous active high reset
+ arst_i : in std_logic := not ARST_LVL; -- asynchronous reset
+ wb_adr_i : in unsigned(2 downto 0); -- lower address bits
+ wb_dat_i : in std_logic_vector(7 downto 0); -- Databus input
+ wb_dat_o : out std_logic_vector(7 downto 0); -- Databus output
+ wb_we_i : in std_logic; -- Write enable input
+ wb_stb_i : in std_logic; -- Strobe signals / core select signal
+ wb_cyc_i : in std_logic; -- Valid bus cycle input
+ wb_ack_o : out std_logic; -- Bus cycle acknowledge output
+ wb_inta_o : out std_logic; -- interrupt request output signal
+
+ -- i2c lines
+ scl_pad_i : in std_logic; -- i2c clock line input
+ scl_pad_o : out std_logic; -- i2c clock line output
+ scl_padoen_o : out std_logic; -- i2c clock line output enable, active low
+ sda_pad_i : in std_logic; -- i2c data line input
+ sda_pad_o : out std_logic; -- i2c data line output
+ sda_padoen_o : out std_logic -- i2c data line output enable, active low
+ );
+end entity i2c_master_top;
+
+architecture structural of i2c_master_top is
+ component i2c_master_byte_ctrl is
+ port (
+ clk : in std_logic;
+ rst : in std_logic; -- synchronous active high reset (WISHBONE compatible)
+ nReset : in std_logic; -- asynchornous active low reset (FPGA compatible)
+ ena : in std_logic; -- core enable signal
+
+ clk_cnt : in unsigned(15 downto 0); -- 4x SCL
+
+ -- input signals
+ start,
+ stop,
+ read,
+ write,
+ ack_in : std_logic;
+ din : in std_logic_vector(7 downto 0);
+
+ -- output signals
+ cmd_ack : out std_logic;
+ ack_out : out std_logic;
+ i2c_busy : out std_logic;
+ i2c_al : out std_logic;
+ dout : out std_logic_vector(7 downto 0);
+
+ -- i2c lines
+ scl_i : in std_logic; -- i2c clock line input
+ scl_o : out std_logic; -- i2c clock line output
+ scl_oen : out std_logic; -- i2c clock line output enable, active low
+ sda_i : in std_logic; -- i2c data line input
+ sda_o : out std_logic; -- i2c data line output
+ sda_oen : out std_logic -- i2c data line output enable, active low
+ );
+ end component i2c_master_byte_ctrl;
+
+ -- registers
+ signal prer : unsigned(15 downto 0); -- clock prescale register
+ signal ctr : std_logic_vector(7 downto 0); -- control register
+ signal txr : std_logic_vector(7 downto 0); -- transmit register
+ signal rxr : std_logic_vector(7 downto 0); -- receive register
+ signal cr : std_logic_vector(7 downto 0); -- command register
+ signal sr : std_logic_vector(7 downto 0); -- status register
+
+ -- internal reset signal
+ signal rst_i : std_logic;
+
+ -- wishbone write access
+ signal wb_wacc : std_logic;
+
+ -- internal acknowledge signal
+ signal iack_o : std_logic;
+
+ -- done signal: command completed, clear command register
+ signal done : std_logic;
+
+ -- command register signals
+ signal sta, sto, rd, wr, ack, iack : std_logic;
+
+ signal core_en : std_logic; -- core enable signal
+ signal ien : std_logic; -- interrupt enable signal
+
+ -- status register signals
+ signal irxack, rxack : std_logic; -- received aknowledge from slave
+ signal tip : std_logic; -- transfer in progress
+ signal irq_flag : std_logic; -- interrupt pending flag
+ signal i2c_busy : std_logic; -- i2c bus busy (start signal detected)
+ signal i2c_al, al : std_logic; -- arbitration lost
+
+begin
+ -- generate internal reset signal
+ rst_i <= arst_i xor ARST_LVL;
+
+ -- generate acknowledge output signal
+ gen_ack_o : process(wb_clk_i)
+ begin
+ if (wb_clk_i'event and wb_clk_i = '1') then
+ iack_o <= wb_cyc_i and wb_stb_i and not iack_o; -- because timing is always honored
+ end if;
+ end process gen_ack_o;
+ wb_ack_o <= iack_o;
+
+
+ -- generate wishbone write access signal
+ wb_wacc <= wb_cyc_i and wb_stb_i and wb_we_i;
+
+ -- assign wb_dat_o
+ assign_dato : process(wb_clk_i)
+ begin
+ if (wb_clk_i'event and wb_clk_i = '1') then
+ case wb_adr_i is
+ when "000" => wb_dat_o <= std_logic_vector(prer( 7 downto 0));
+ when "001" => wb_dat_o <= std_logic_vector(prer(15 downto 8));
+ when "010" => wb_dat_o <= ctr;
+ when "011" => wb_dat_o <= rxr; -- write is transmit register TxR
+ when "100" => wb_dat_o <= sr; -- write is command register CR
+
+ -- Debugging registers:
+ -- These registers are not documented.
+ -- Functionality could change in future releases
+ when "101" => wb_dat_o <= txr;
+ when "110" => wb_dat_o <= cr;
+ when "111" => wb_dat_o <= (others => '0');
+ when others => wb_dat_o <= (others => 'X'); -- for simulation only
+ end case;
+ end if;
+ end process assign_dato;
+
+
+ -- generate registers (CR, SR see below)
+ gen_regs: process(rst_i, wb_clk_i)
+ begin
+ if (rst_i = '0') then
+ prer <= (others => '1');
+ ctr <= (others => '0');
+ txr <= (others => '0');
+ elsif (wb_clk_i'event and wb_clk_i = '1') then
+ if (wb_rst_i = '1') then
+ prer <= (others => '1');
+ ctr <= (others => '0');
+ txr <= (others => '0');
+ elsif (wb_wacc = '1') then
+ case wb_adr_i is
+ when "000" => prer( 7 downto 0) <= unsigned(wb_dat_i);
+ when "001" => prer(15 downto 8) <= unsigned(wb_dat_i);
+ when "010" => ctr <= wb_dat_i;
+ when "011" => txr <= wb_dat_i;
+ when "100" => null; --write to CR, avoid executing the others clause
+
+ -- illegal cases, for simulation only
+ when others =>
+ report ("Illegal write address, setting all registers to unknown.");
+ prer <= (others => 'X');
+ ctr <= (others => 'X');
+ txr <= (others => 'X');
+ end case;
+ end if;
+ end if;
+ end process gen_regs;
+
+
+ -- generate command register
+ gen_cr: process(rst_i, wb_clk_i)
+ begin
+ if (rst_i = '0') then
+ cr <= (others => '0');
+ elsif (wb_clk_i'event and wb_clk_i = '1') then
+ if (wb_rst_i = '1') then
+ cr <= (others => '0');
+ elsif (wb_wacc = '1') then
+ if ( (core_en = '1') and (wb_adr_i = 4) ) then
+ -- only take new commands when i2c core enabled
+ -- pending commands are finished
+ cr <= wb_dat_i;
+ end if;
+ else
+ if (done = '1' or i2c_al = '1') then
+ cr(7 downto 4) <= (others => '0'); -- clear command bits when command done or arbitration lost
+ end if;
+
+ cr(2 downto 1) <= (others => '0'); -- reserved bits, always '0'
+ cr(0) <= '0'; -- clear IRQ_ACK bit
+ end if;
+ end if;
+ end process gen_cr;
+
+ -- decode command register
+ sta <= cr(7);
+ sto <= cr(6);
+ rd <= cr(5);
+ wr <= cr(4);
+ ack <= cr(3);
+ iack <= cr(0);
+
+ -- decode control register
+ core_en <= ctr(7);
+ ien <= ctr(6);
+
+ -- hookup byte controller block
+ byte_ctrl: i2c_master_byte_ctrl port map (
+ clk => wb_clk_i,
+ rst => wb_rst_i,
+ nReset => rst_i,
+ ena => core_en,
+ clk_cnt => prer,
+ start => sta,
+ stop => sto,
+ read => rd,
+ write => wr,
+ ack_in => ack,
+ i2c_busy => i2c_busy,
+ i2c_al => i2c_al,
+ din => txr,
+ cmd_ack => done,
+ ack_out => irxack,
+ dout => rxr,
+ scl_i => scl_pad_i,
+ scl_o => scl_pad_o,
+ scl_oen => scl_padoen_o,
+ sda_i => sda_pad_i,
+ sda_o => sda_pad_o,
+ sda_oen => sda_padoen_o
+ );
+
+
+ -- status register block + interrupt request signal
+ st_irq_block : block
+ begin
+ -- generate status register bits
+ gen_sr_bits: process (wb_clk_i, rst_i)
+ begin
+ if (rst_i = '0') then
+ al <= '0';
+ rxack <= '0';
+ tip <= '0';
+ irq_flag <= '0';
+ elsif (wb_clk_i'event and wb_clk_i = '1') then
+ if (wb_rst_i = '1') then
+ al <= '0';
+ rxack <= '0';
+ tip <= '0';
+ irq_flag <= '0';
+ else
+ al <= i2c_al or (al and not sta);
+ rxack <= irxack;
+ tip <= (rd or wr);
+
+ -- interrupt request flag is always generated
+ irq_flag <= (done or i2c_al or irq_flag) and not iack;
+ end if;
+ end if;
+ end process gen_sr_bits;
+
+ -- generate interrupt request signals
+ gen_irq: process (wb_clk_i, rst_i)
+ begin
+ if (rst_i = '0') then
+ wb_inta_o <= '0';
+ elsif (wb_clk_i'event and wb_clk_i = '1') then
+ if (wb_rst_i = '1') then
+ wb_inta_o <= '0';
+ else
+ -- interrupt signal is only generated when IEN (interrupt enable bit) is set
+ wb_inta_o <= irq_flag and ien;
+ end if;
+ end if;
+ end process gen_irq;
+
+ -- assign status register bits
+ sr(7) <= rxack;
+ sr(6) <= i2c_busy;
+ sr(5) <= al;
+ sr(4 downto 2) <= (others => '0'); -- reserved
+ sr(1) <= tip;
+ sr(0) <= irq_flag;
+ end block;
+
+end architecture structural;
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/readme b/fpga/usrp2/opencores/i2c/rtl/vhdl/readme
new file mode 100644
index 000000000..0d049f736
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/readme
@@ -0,0 +1,25 @@
+
+
+-- This code is provided for free and may be used and --
+-- distributed without restriction provided that the --
+-- copyright statement is not removed from the file and --
+-- that any derivative work contains the original --
+-- copyright notice and the associated disclaimer. --
+
+-- Comments and suggestions are always welcome --
+
+The i2c_master core consists of three files:
+
+- i2c_master_top -- top level
+- i2c_master_byte_ctrl -- byte controller
+- i2c_master_bit_ctrl -- bit controller
+
+VHDL needs to be compiled in order. The files are listed
+above in descending order.
+
+I2C.VHD and tst_ds1621.vhd are not supported anymore.
+They remain mostly for historical purposes, altough they
+might prove usefull.
+
+Richard Herveille
+rherveille@opencores.org
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd b/fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd
new file mode 100644
index 000000000..ccf50460c
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd
@@ -0,0 +1,283 @@
+--
+--
+-- State machine for reading data from Dallas 1621
+--
+-- Testsystem for i2c controller
+--
+--
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.std_logic_arith.all;
+
+use work.i2c.all;
+
+entity DS1621_interface is
+ port (
+ clk : in std_logic;
+ nReset : in std_logic;
+
+ Dout : out std_logic_vector(7 downto 0); -- data read from ds1621
+
+ error : out std_logic; -- no correct ack received
+
+ SCL : inout std_logic;
+ SDA : inout std_logic
+ );
+end entity DS1621_interface;
+
+architecture structural of DS1621_interface is
+ constant SLAVE_ADDR : std_logic_vector(6 downto 0) := "1001000";
+ constant CLK_CNT : unsigned(7 downto 0) := conv_unsigned(20, 8);
+
+ signal cmd_ack : std_logic;
+ signal D : std_logic_vector(7 downto 0);
+ signal lack, store_dout : std_logic;
+
+ signal start, read, write, ack, stop : std_logic;
+ signal i2c_dout : std_logic_vector(7 downto 0);
+
+begin
+ -- hookup I2C controller
+ u1: simple_i2c port map (clk => clk, ena => '1', clk_cnt => clk_cnt, nReset => nReset,
+ read => read, write => write, start => start, stop => stop, ack_in => ack, cmd_ack => cmd_ack,
+ Din => D, Dout => i2c_dout, ack_out => lack, SCL => SCL, SDA => SDA);
+
+ init_statemachine : block
+ type states is (i1, i2, i3, i4, i5, t1, t2, t3, t4, t5);
+ signal state : states;
+ begin
+ nxt_state_decoder: process(clk, nReset, state)
+ variable nxt_state : states;
+ variable iD : std_logic_vector(7 downto 0);
+ variable ierr : std_logic;
+ variable istart, iread, iwrite, iack, istop : std_logic;
+ variable istore_dout : std_logic;
+ begin
+ nxt_state := state;
+ ierr := '0';
+ istore_dout := '0';
+
+ istart := start;
+ iread := read;
+ iwrite := write;
+ iack := ack;
+ istop := stop;
+ iD := D;
+
+ case (state) is
+ -- init DS1621
+ -- 1) send start condition
+ -- 2) send slave address + write
+ -- 3) check ack
+ -- 4) send "access config" command (0xAC)
+ -- 5) check ack
+ -- 6) send config register data (0x00)
+ -- 7) check ack
+ -- 8) send stop condition
+ -- 9) send start condition
+ -- 10) send slave address + write
+ -- 11) check ack
+ -- 12) send "start conversion" command (0xEE)
+ -- 13) check ack
+ -- 14) send stop condition
+
+ when i1 => -- send start condition, sent slave address + write
+ nxt_state := i2;
+ istart := '1';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := (slave_addr & '0'); -- write to slave (R/W = '0')
+
+ when i2 => -- send "access config" command
+ if (cmd_ack = '1') then
+ nxt_state := i3;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '0';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := x"AC";
+ end if;
+
+ when i3 => -- send config register data, sent stop condition
+ if (cmd_ack = '1') then
+ nxt_state := i4;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '0';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '1';
+ iD := x"00";
+ end if;
+
+ when i4 => -- send start condition, sent slave address + write
+ if (cmd_ack = '1') then
+ nxt_state := i5;
+
+ istart := '1';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := (slave_addr & '0'); -- write to slave (R/W = '0')
+ end if;
+
+ when i5 => -- send "start conversion" command + stop condition
+ if (cmd_ack = '1') then
+ nxt_state := t1;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '0';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '1';
+ iD := x"EE";
+ end if;
+ -- read temperature
+ -- 1) sent start condition
+ -- 2) sent slave address + write
+ -- 3) check ack
+ -- 4) sent "read temperature" command (0xAA)
+ -- 5) check ack
+ -- 6) sent start condition
+ -- 7) sent slave address + read
+ -- 8) check ack
+ -- 9) read msb
+ -- 10) send ack
+ -- 11) read lsb
+ -- 12) send nack
+ -- 13) send stop condition
+
+ when t1 => -- send start condition, sent slave address + write
+ if (cmd_ack = '1') then
+ nxt_state := t2;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '1';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := (slave_addr & '0'); -- write to slave (R/W = '0')
+ end if;
+
+ when t2 => -- send read temperature command
+ if (cmd_ack = '1') then
+ nxt_state := t3;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '0';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := x"AA";
+ end if;
+
+ when t3 => -- send (repeated) start condition, send slave address + read
+ if (cmd_ack = '1') then
+ nxt_state := t4;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received, expected ACK
+ end if;
+
+ istart := '1';
+ iread := '0';
+ iwrite := '1';
+ iack := '0';
+ istop := '0';
+ iD := (slave_addr & '1'); -- read from slave (R/W = '1')
+ end if;
+
+ when t4 => -- read MSB (hi-byte), send acknowledge
+ if (cmd_ack = '1') then
+ nxt_state := t5;
+ -- check aknowledge bit
+ if (lack = '1') then
+ ierr := '1'; -- no acknowledge received from last command, expected ACK
+ end if;
+
+ istart := '0';
+ iread := '1';
+ iwrite := '0';
+ iack := '0'; --ACK
+ istop := '0';
+ end if;
+
+ when t5 => -- read LSB (lo-byte), send acknowledge, sent stop
+ if (cmd_ack = '1') then
+ nxt_state := t1;
+
+ istart := '0';
+ iread := '1';
+ iwrite := '0';
+ iack := '1'; --NACK
+ istop := '1';
+
+ istore_dout := '1';
+ end if;
+ end case;
+
+ -- genregs
+ if (nReset = '0') then
+ state <= i1;
+ error <= '0';
+ store_dout <= '0';
+
+ start <= '0';
+ read <= '0';
+ write <= '0';
+ ack <= '0';
+ stop <= '0';
+ D <= (others => '0');
+ elsif (clk'event and clk = '1') then
+ state <= nxt_state;
+ error <= ierr;
+ store_dout <= istore_dout;
+
+ start <= istart;
+ read <= iread;
+ write <= iwrite;
+ ack <= iack;
+ stop <= istop;
+ D <= iD;
+ end if;
+ end process nxt_state_decoder;
+ end block init_statemachine;
+
+ -- store temp
+ gen_dout : process(clk)
+ begin
+ if (clk'event and clk = '1') then
+ if (store_dout = '1') then
+ Dout <= i2c_dout;
+ end if;
+ end if;
+ end process gen_dout;
+
+end architecture structural;
+
+
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-13 04:52:39 +0000