I2C Module from Opencores
diff --git a/verilog/rtl/i2c/i2c_master_bit_ctrl.v b/verilog/rtl/i2c/i2c_master_bit_ctrl.v new file mode 100644 index 0000000..96cc325 --- /dev/null +++ b/verilog/rtl/i2c/i2c_master_bit_ctrl.v
@@ -0,0 +1,572 @@ +///////////////////////////////////////////////////////////////////// +//// //// +//// 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 1.14 2009-01-20 10:25:29 rherveille Exp $ +// +// $Date: 2009-01-20 10:25:29 $ +// $Revision: 1.14 $ +// $Author: rherveille $ +// $Locker: $ +// $State: Exp $ +// +// Change History: +// $Log: $ +// Revision 1.14 2009/01/20 10:25:29 rherveille +// Added clock synchronization logic +// Fixed slave_wait signal +// +// Revision 1.13 2009/01/19 20:29:26 rherveille +// Fixed cr[0] register width +// Fixed ! usage instead of ~ +// Fixed bit controller parameter width to 18bits +// +// 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 +// + + +`include "i2c_master_defines.v" + +module i2c_master_bit_ctrl ( + input clk, // system clock + input rst, // synchronous active high reset + input nReset, // asynchronous active low reset + input ena, // core enable signal + + input [15:0] clk_cnt, // clock prescale value + + input [ 3:0] cmd, // command (from byte controller) + output reg cmd_ack, // command complete acknowledge + output reg busy, // i2c bus busy + output reg al, // i2c bus arbitration lost + + input din, + output reg dout, + + input scl_i, // i2c clock line input + output scl_o, // i2c clock line output + output reg scl_oen, // i2c clock line output enable (active low) + input sda_i, // i2c data line input + output sda_o, // i2c data line output + output reg sda_oen // i2c data line output enable (active low) +); + + + // + // variable declarations + // + + reg [ 1:0] cSCL, cSDA; // capture SCL and SDA + reg [ 2:0] fSCL, fSDA; // SCL and SDA filter inputs + reg sSCL, sSDA; // filtered and synchronized SCL and SDA inputs + reg dSCL, dSDA; // delayed versions of sSCL and sSDA + reg dscl_oen; // delayed scl_oen + reg sda_chk; // check SDA output (Multi-master arbitration) + reg clk_en; // clock generation signals + reg slave_wait; // slave inserts wait states + reg [15:0] cnt; // clock divider counter (synthesis) + reg [13:0] filter_cnt; // clock divider for filter + + + // state machine variable + reg [17:0] c_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; + + // slave_wait is asserted when master wants to drive SCL high, but the slave pulls it low + // slave_wait remains asserted until the slave releases SCL + always @(posedge clk or negedge nReset) + if (!nReset) slave_wait <= 1'b0; + else slave_wait <= (scl_oen & ~dscl_oen & ~sSCL) | (slave_wait & ~sSCL); + + // master drives SCL high, but another master pulls it low + // master start counting down its low cycle now (clock synchronization) + wire scl_sync = dSCL & ~sSCL & scl_oen; + + + // 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 || ~|cnt || !ena || scl_sync) + 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 + + // capture SDA and SCL + // reduce metastability risk + always @(posedge clk or negedge nReset) + if (!nReset) + begin + cSCL <= #1 2'b00; + cSDA <= #1 2'b00; + end + else if (rst) + begin + cSCL <= #1 2'b00; + cSDA <= #1 2'b00; + end + else + begin + cSCL <= {cSCL[0],scl_i}; + cSDA <= {cSDA[0],sda_i}; + end + + + // filter SCL and SDA signals; (attempt to) remove glitches + always @(posedge clk or negedge nReset) + if (!nReset ) filter_cnt <= 14'h0; + else if (rst || !ena ) filter_cnt <= 14'h0; + else if (~|filter_cnt) filter_cnt <= clk_cnt >> 2; //16x I2C bus frequency + else filter_cnt <= filter_cnt -1; + + + always @(posedge clk or negedge nReset) + if (!nReset) + begin + fSCL <= 3'b111; + fSDA <= 3'b111; + end + else if (rst) + begin + fSCL <= 3'b111; + fSDA <= 3'b111; + end + else if (~|filter_cnt) + begin + fSCL <= {fSCL[1:0],cSCL[1]}; + fSDA <= {fSDA[1:0],cSDA[1]}; + end + + + // generate filtered SCL and SDA signals + 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 &fSCL[2:1] | &fSCL[1:0] | (fSCL[2] & fSCL[0]); + sSDA <= #1 &fSDA[2:1] | &fSDA[1:0] | (fSDA[2] & fSDA[0]); + + 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 + reg sta_condition; + reg sto_condition; + 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 [17:0] idle = 18'b0_0000_0000_0000_0000; + parameter [17:0] start_a = 18'b0_0000_0000_0000_0001; + parameter [17:0] start_b = 18'b0_0000_0000_0000_0010; + parameter [17:0] start_c = 18'b0_0000_0000_0000_0100; + parameter [17:0] start_d = 18'b0_0000_0000_0000_1000; + parameter [17:0] start_e = 18'b0_0000_0000_0001_0000; + parameter [17:0] stop_a = 18'b0_0000_0000_0010_0000; + parameter [17:0] stop_b = 18'b0_0000_0000_0100_0000; + parameter [17:0] stop_c = 18'b0_0000_0000_1000_0000; + parameter [17:0] stop_d = 18'b0_0000_0001_0000_0000; + parameter [17:0] rd_a = 18'b0_0000_0010_0000_0000; + parameter [17:0] rd_b = 18'b0_0000_0100_0000_0000; + parameter [17:0] rd_c = 18'b0_0000_1000_0000_0000; + parameter [17:0] rd_d = 18'b0_0001_0000_0000_0000; + parameter [17:0] wr_a = 18'b0_0010_0000_0000_0000; + parameter [17:0] wr_b = 18'b0_0100_0000_0000_0000; + parameter [17:0] wr_c = 18'b0_1000_0000_0000_0000; + parameter [17:0] wr_d = 18'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) + // idle state + idle: + begin + case (cmd) + `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'b0; // don't check SDA output yet + // allow some time for SDA and SCL to settle + 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/verilog/rtl/i2c/i2c_master_byte_ctrl.v b/verilog/rtl/i2c/i2c_master_byte_ctrl.v new file mode 100644 index 0000000..613dda3 --- /dev/null +++ b/verilog/rtl/i2c/i2c_master_byte_ctrl.v
@@ -0,0 +1,341 @@ +///////////////////////////////////////////////////////////////////// +//// //// +//// 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 1.8 2009-01-19 20:29:26 rherveille Exp $ +// +// $Date: 2009-01-19 20:29:26 $ +// $Revision: 1.8 $ +// $Author: rherveille $ +// $Locker: $ +// $State: Exp $ +// +// Change History: +// $Log: not supported by cvs2svn $ +// 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. +// + + +`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; + + 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) + 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/verilog/rtl/i2c/i2c_master_defines.v b/verilog/rtl/i2c/i2c_master_defines.v new file mode 100644 index 0000000..e81c546 --- /dev/null +++ b/verilog/rtl/i2c/i2c_master_defines.v
@@ -0,0 +1,59 @@ +///////////////////////////////////////////////////////////////////// +//// //// +//// 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: not supported by cvs2svn $ + + +// 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/verilog/rtl/i2c/i2c_master_top.v b/verilog/rtl/i2c/i2c_master_top.v new file mode 100644 index 0000000..e7c9dff --- /dev/null +++ b/verilog/rtl/i2c/i2c_master_top.v
@@ -0,0 +1,297 @@ +///////////////////////////////////////////////////////////////////// +//// //// +//// 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 1.12 2009-01-19 20:29:26 rherveille Exp $ +// +// $Date: 2009-01-19 20:29:26 $ +// $Revision: 1.12 $ +// $Author: rherveille $ +// $Locker: $ +// $State: Exp $ +// +// Change History: +// 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. +// + + +`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_we_i & wb_ack_o; + + // 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) + 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) + 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 1'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/verilog/rtl/i2c/timescale.v b/verilog/rtl/i2c/timescale.v new file mode 100644 index 0000000..60d4ecb --- /dev/null +++ b/verilog/rtl/i2c/timescale.v
@@ -0,0 +1,2 @@ +`timescale 1ns / 10ps +