fpga: added setting regs based simple_i2c_core

2 files changed, 117 insertions, 0 deletions

diff --git a/usrp2/control_lib/Makefile.srcs b/usrp2/control_lib/Makefile.srcs
index 0bb9a3efe..42862a50f 100644
--- a/usrp2/control_lib/Makefile.srcs
+++ b/usrp2/control_lib/Makefile.srcs
@@ -57,4 +57,5 @@ gpio_atr.v \
 user_settings.v \
 settings_fifo_ctrl.v \
 simple_spi_core.v \
+simple_i2c_core.v \
 ))
diff --git a/usrp2/control_lib/simple_i2c_core.v b/usrp2/control_lib/simple_i2c_core.v
new file mode 100644
index 000000000..9c61de8fb
--- /dev/null
+++ b/usrp2/control_lib/simple_i2c_core.v
@@ -0,0 +1,116 @@
+//
+// Copyright 2012 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+// Simple I2C core
+
+// Settings reg map:
+//
+// BASE+0 control register
+//   byte0 - control bits, data byte, or command bits, prescaler
+//   byte1 - what to do? (documented in cpp file)
+//      write prescaler lo
+//      write prescaler hi
+//      write control
+//      write data
+//      write command
+//      read data
+//      read status
+//
+
+// Readback:
+//
+// byte0 has readback value based on the last read command
+//
+
+module simple_i2c_core
+    #(
+        //settings register base address
+        parameter BASE = 0,
+
+        //i2c line level at reset
+        parameter ARST_LVL = 1
+    )
+    (
+        //clock and synchronous reset
+        input clock, input reset,
+
+        //32-bit settings bus inputs
+        input set_stb, input [7:0] set_addr, input [31:0] set_data,
+
+        //32-bit data readback
+        output reg [31:0] readback,
+
+        //read is high when i2c core can begin another transaction
+        output reg ready,
+
+        // 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)
+
+        //optional debug output
+        output [31:0] debug
+    );
+
+    //declare command settings register
+    wire [7:0] sr_what, sr_data;
+    wire sr_changed;
+    setting_reg #(.my_addr(BASE+0),.width(16)) i2c_cmd_sr(
+        .clk(clock),.rst(reset),.strobe(set_stb),.addr(set_addr),.in(set_data),
+        .out({sr_what, sr_data}),.changed(sr_changed));
+
+    //declare wb interface signals
+    wire [2:0] wb_addr;
+    wire [7:0] wb_data_mosi;
+    wire [7:0] wb_data_miso;
+    wire wb_we, wb_stb, wb_cyc;
+    wire wb_ack;
+
+    //create wishbone-based i2c core
+    i2c_master_top #(.ARST_LVL(ARST_LVL)) i2c 
+     (.wb_clk_i(clock),.wb_rst_i(reset),.arst_i(1'b0), 
+      .wb_adr_i(wb_addr),.wb_dat_i(wb_data_mosi),.wb_dat_o(wb_data_miso),
+      .wb_we_i(wb_we),.wb_stb_i(wb_stb),.wb_cyc_i(wb_cyc),
+      .wb_ack_o(wb_ack),.wb_inta_o(),
+      .scl_pad_i(scl_pad_i),.scl_pad_o(scl_pad_o),.scl_padoen_o(scl_padoen_o),
+      .sda_pad_i(sda_pad_i),.sda_pad_o(sda_pad_o),.sda_padoen_o(sda_padoen_o) );
+
+    //not ready between setting register and wishbone ack
+    always @(posedge clock) begin
+        if (reset || wb_ack) ready <= 1;
+        else if (sr_changed) ready <= 0;
+    end
+
+    //register wishbone data on every ack
+    always @(posedge clock) begin
+        if (wb_ack) readback <= {24'b0, wb_data_miso};
+    end
+
+    //assign wishbone signals
+    assign wb_addr = sr_what[2:0];
+    assign wb_stb = sr_changed;
+    assign wb_we = wb_stb && sr_what[3];
+    assign wb_cyc = wb_stb;
+    assign wb_data_mosi = sr_data;
+
+endmodule //simple_i2c_core