From 05d77f772317de5d925301aa11bb9a880656dd05 Mon Sep 17 00:00:00 2001
From: Josh Blum <josh@joshknows.com>
Date: Thu, 15 Apr 2010 11:24:24 -0700
Subject: moved usrp1 and usrp2 fpga dirs into fpga subdirectory
---
fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Entries | 7 +
fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Repository | 1 +
fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Root | 1 +
fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Template | 0
fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD | 620 +++++++++++++++++++++
.../opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd | 495 ++++++++++++++++
.../i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd | 370 ++++++++++++
.../opencores/i2c/rtl/vhdl/i2c_master_top.vhd | 359 ++++++++++++
fpga/usrp2/opencores/i2c/rtl/vhdl/readme | 25 +
fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd | 283 ++++++++++
10 files changed, 2161 insertions(+)
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Entries
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Repository
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Root
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Template
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/I2C.VHD
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_bit_ctrl.vhd
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_byte_ctrl.vhd
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/i2c_master_top.vhd
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/readme
create mode 100644 fpga/usrp2/opencores/i2c/rtl/vhdl/tst_ds1621.vhd
(limited to 'fpga/usrp2/opencores/i2c/rtl/vhdl')
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Entries b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Entries
new file mode 100644
index 000000000..2a33278f7
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Entries
@@ -0,0 +1,7 @@
+/I2C.VHD/1.1/Mon Sep 24 12:21:51 2001//
+/i2c_master_bit_ctrl.vhd/1.14/Wed Oct 11 12:10:13 2006//
+/i2c_master_byte_ctrl.vhd/1.5/Wed Feb 18 11:41:48 2004//
+/i2c_master_top.vhd/1.7/Sun Mar 14 10:17:03 2004//
+/readme/1.2/Sat Nov 30 22:25:47 2002//
+/tst_ds1621.vhd/1.1/Mon Sep 24 12:21:51 2001//
+D
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Repository b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Repository
new file mode 100644
index 000000000..c210ff4e3
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Repository
@@ -0,0 +1 @@
+i2c/rtl/vhdl
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Root b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Root
new file mode 100644
index 000000000..44b2aa23b
--- /dev/null
+++ b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Root
@@ -0,0 +1 @@
+:pserver:anonymous@cvs.opencores.org:/cvsroot/anonymous
diff --git a/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Template b/fpga/usrp2/opencores/i2c/rtl/vhdl/CVS/Template
new file mode 100644
index 000000000..e69de29bb
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;
+
+
--
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