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/////////////////////////////////////////////////////////////////////
////                                                             ////
////  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.
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
 
`include "i2c_master_slave_defines.v"
 
module i2c_master_byte_ctrl
  (
   clk, my_addr, rst, nReset, ena, clk_cnt, start, stop, read, write, ack_in,
   din, cmd_ack, ack_out, dout, i2c_busy, i2c_al, scl_i, sl_cont, scl_o,
   scl_oen, sda_i, sda_o, sda_oen,slave_dat_req, slave_en, slave_dat_avail,
   slave_act, slave_cmd_ack
   );
 
 
   //
   // inputs & outputs
   //
   input clk;     // master clock
   input my_addr; // Slave address input
   input rst;     // synchronous active high reset
   input nReset;  // asynchronous active low reset
   input ena;     // core enable signal
   input sl_cont;
   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;
   input        slave_en;
   output reg   slave_dat_req;
   output reg   slave_dat_avail;
   output reg   slave_act;
   output reg   slave_cmd_ack;
   //
   // Variable declarations
   //
 
   // statemachine
   parameter [9:0] ST_IDLE       = 10'b00_0000_0000;
   parameter [9:0] ST_START      = 10'b00_0000_0001;
   parameter [9:0] ST_READ       = 10'b00_0000_0010;
   parameter [9:0] ST_WRITE      = 10'b00_0000_0100;
   parameter [9:0] ST_ACK        = 10'b00_0000_1000;
   parameter [9:0] ST_STOP       = 10'b00_0001_0000;
   parameter [9:0] ST_SL_ACK     = 10'b00_0010_0000;
   parameter [9:0] ST_SL_RD      = 10'b00_0100_0000;
   parameter [9:0] ST_SL_WR      = 10'b00_1000_0000;
   parameter [9:0] ST_SL_WAIT    = 10'b01_0000_0000;
   parameter [9:0] ST_SL_PRELOAD = 10'b10_0000_0000;
 
 
   reg          sl_wait;
   // signals for bit_controller
   wire [6:0]    my_addr;
   reg [3:0]     core_cmd;
   reg          core_txd;
   wire         core_ack, core_rxd;
   wire         sl_cont;
   // signals for shift register
   reg [7:0]     sr; //8bit shift register
   reg          shift, ld;
   reg          master_mode;
   reg [1:0]     slave_cmd_out;
   // signals for state machine
   wire         go;
   reg [2:0]     dcnt;
   wire         cnt_done;
   wire         slave_ack;
 
 
   //Slave signals
   wire         slave_adr_received;
   wire [7:0]    slave_adr;
 
 
   reg [1:0]     slave_cmd;
   //
   // 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  ),
      .slave_adr_received ( slave_adr_received  ),
      .slave_adr  ( slave_adr  ),
      .master_mode (master_mode),
      .cmd_slave_ack (slave_ack),
      .slave_cmd (slave_cmd_out),
      .sl_wait (sl_wait),
      .slave_reset (slave_reset)
      );
 
   reg          slave_adr_received_d;
   // generate go-signal
   assign go = (read | write | stop) & ~cmd_ack;
 
   // assign dout output to shift-register
   assign dout = sr;
 
   always @(posedge clk or negedge nReset)
     if (!nReset)
       slave_adr_received_d <=  1'b0;
     else
       slave_adr_received_d <=   slave_adr_received;
 
   // generate shift register
   always @(posedge clk or negedge nReset)
     if (!nReset)
       sr <=  8'h0;
     else if (rst)
       sr <=  8'h0;
     else if (ld)
       sr <=  din;
     else if (shift)
       sr <=  {sr[6:0], core_rxd};
     else if (slave_adr_received_d & slave_act)
       sr <=  {slave_adr[7:1], 1'b0};
 
 
 
   // generate counter
   always @(posedge clk or negedge nReset)
     if (!nReset)
       dcnt <=  3'h0;
     else if (rst)
       dcnt <=  3'h0;
     else if (ld)
       dcnt <=  3'h7;
 
     else if (shift)
       dcnt <=  dcnt - 3'h1;
 
   assign cnt_done = ~(|dcnt);
 
   //
   // state machine
   //
   reg [9:0]     c_state; // synopsys enum_state
 
 
 
   always @(posedge clk or negedge nReset)
     if (!nReset)
       begin
          sl_wait <=  1'b0;
          core_cmd <=  `I2C_CMD_NOP;
          core_txd <=  1'b0;
          shift    <=  1'b0;
          ld       <=  1'b0;
          cmd_ack  <=  1'b0;
          c_state  <=  ST_IDLE;
          ack_out  <=  1'b0;
          master_mode <=  1'b0;
          slave_cmd  <=  2'b0;
          slave_dat_req <=  1'b0;
          slave_dat_avail       <=  1'b0;
          slave_act <=  1'b0;
          slave_cmd_out <=  2'b0;
          slave_cmd_ack <=  1'b0;
       end
     else if (rst | i2c_al | slave_reset)
       begin
          core_cmd <=  `I2C_CMD_NOP;
          core_txd <=  1'b0;
          shift    <=  1'b0;
          sl_wait  <=  1'b0;
          ld       <=  1'b0;
          cmd_ack  <=  1'b0;
          c_state  <=  ST_IDLE;
          ack_out  <=  1'b0;
          master_mode <=  1'b0;
          slave_cmd  <=  2'b0;
          slave_cmd_out <=  2'b0;
          slave_dat_req <=  1'b0;
          slave_dat_avail       <=  1'b0;
          slave_act <=  1'b0;
          slave_cmd_ack <=  1'b0;
       end
     else
       begin
          slave_cmd_out <=  slave_cmd;
          // initially reset all signals
          core_txd <=  sr[7];
          shift    <=  1'b0;
          ld       <=  1'b0;
          cmd_ack  <=  1'b0;
          slave_cmd_ack <=  1'b0;
 
          case (c_state) // synopsys full_case parallel_case
            ST_IDLE:
              begin
                 slave_act <=  1'b0;
                 if (slave_en & slave_adr_received &
                     (slave_adr[7:1] == my_addr )) begin
 
                    c_state  <=  ST_SL_ACK;
                    master_mode <=  1'b0;
                    slave_act <=  1'b1;
                    slave_cmd <=  `I2C_SLAVE_CMD_WRITE;
                    core_txd <=  1'b0;
 
                 end
                 else if (go && !slave_act )
                   begin
                      if (start )
                        begin
                           c_state  <=  ST_START;
                           core_cmd <=  `I2C_CMD_START;
                           master_mode <=  1'b1;
                        end
                      else if (read)
                        begin
                           c_state  <=  ST_READ;
                           core_cmd <=  `I2C_CMD_READ;
                        end
                      else if (write)
                        begin
                           c_state  <=  ST_WRITE;
                           core_cmd <=  `I2C_CMD_WRITE;
                        end
                      else // stop
                        begin
                           c_state  <=  ST_STOP;
                           core_cmd <=  `I2C_CMD_STOP;
 
                        end
 
                      ld <=  1'b1;
                   end
 
              end
            ST_SL_RD: //If master read, slave sending data
              begin
                 slave_cmd <=  `I2C_SLAVE_CMD_NOP;
                 if (slave_ack) begin
                    if (cnt_done) begin
                       c_state   <=  ST_SL_ACK;
                       slave_cmd <=  `I2C_SLAVE_CMD_READ;
                    end
                    else
                      begin
                         c_state   <=  ST_SL_RD;
                         slave_cmd <=  `I2C_SLAVE_CMD_WRITE;
                         shift     <=  1'b1;
                      end
                 end
              end
            ST_SL_WR: //If master write, slave reading data   
              begin
                 slave_cmd <=  `I2C_SLAVE_CMD_NOP;
                 if (slave_ack)
                   begin
                      if (cnt_done)
                        begin
                           c_state  <=  ST_SL_ACK;
                           slave_cmd <=  `I2C_SLAVE_CMD_WRITE;
                           core_txd <=  1'b0;
                        end
                      else
                        begin
                           c_state  <=  ST_SL_WR;
                           slave_cmd <=  `I2C_SLAVE_CMD_READ;
                        end
                      shift    <=  1'b1;
                   end
              end
            ST_SL_WAIT: //Wait for interupt-clear and hold SCL in waitstate
              begin
                 sl_wait <=  1'b1;
                 if (sl_cont) begin
                    sl_wait <=  1'b0;
                    ld <=  1'b1;
                    slave_dat_req       <=  1'b0;
                    slave_dat_avail     <=  1'b0;
                    c_state   <=  ST_SL_PRELOAD;
                 end
              end
 
            ST_SL_PRELOAD:
              if (slave_adr[0]) begin
                 c_state   <=  ST_SL_RD;
                 slave_cmd <=  `I2C_SLAVE_CMD_WRITE;
              end
              else begin
                 c_state  <=  ST_SL_WR;
                 slave_cmd <=  `I2C_SLAVE_CMD_READ;
              end
 
            ST_SL_ACK:
              begin
                 slave_cmd <=  `I2C_SLAVE_CMD_NOP;
                 if (slave_ack)  begin
                    ack_out <=  core_rxd;
                    slave_cmd_ack  <=  1'b1;
                    if (!core_rxd) begin // Valid ack recived
                       // generate slave command acknowledge signal if 
                       // succesful transfer                      
                       c_state   <=  ST_SL_WAIT;
                       if (slave_adr[0]) begin // I2C read request
                          slave_dat_req <=  1'b1;
                       end
                       else begin              // I2C write request
                          slave_dat_avail       <=  1'b1;
                       end
                    end
                    else begin
                       c_state   <=  ST_IDLE;
                    end
                 end
                 else begin
                    core_txd <=  1'b0;
                 end
              end
 
            ST_START:
              if (core_ack)
                begin
                   if (read)
                     begin
                        c_state  <=  ST_READ;
                        core_cmd <=  `I2C_CMD_READ;
                     end
                   else
                     begin
                        c_state  <=  ST_WRITE;
                        core_cmd <=  `I2C_CMD_WRITE;
                     end
 
                   ld <=  1'b1;
                end
 
            ST_WRITE:
              if (core_ack)
                if (cnt_done)
                  begin
                     c_state  <=  ST_ACK;
                     core_cmd <=  `I2C_CMD_READ;
                  end
                else
                  begin
                     c_state  <=  ST_WRITE;       // stay in same state
                     core_cmd <=  `I2C_CMD_WRITE; // write next bit
                     shift    <=  1'b1;
                  end
 
            ST_READ:
              if (core_ack)
                begin
                   if (cnt_done)
                     begin
                        c_state  <=  ST_ACK;
                        core_cmd <=  `I2C_CMD_WRITE;
                     end
                   else
                     begin
                        c_state  <=  ST_READ;       // stay in same state
                        core_cmd <=  `I2C_CMD_READ; // read next bit
                     end
 
                   shift    <=  1'b1;
                   core_txd <=  ack_in;
                end
 
            ST_ACK:
              if (core_ack)
                begin
                   if (stop)
                     begin
                        c_state  <=  ST_STOP;
                        core_cmd <=  `I2C_CMD_STOP;
                     end
                   else
                     begin
                        c_state  <=  ST_IDLE;
                        core_cmd <=  `I2C_CMD_NOP;
 
                        // generate command acknowledge signal
                        cmd_ack  <=  1'b1;
                     end
 
                   // assign ack_out output to bit_controller_rxd (contains 
                   // last received bit)
                   ack_out <=  core_rxd;
 
                   core_txd <=  1'b1;
                end
              else
                core_txd <=  ack_in;
 
            ST_STOP:
              if (core_ack)
                begin
                   c_state  <=  ST_IDLE;
                   core_cmd <=  `I2C_CMD_NOP;
 
                   // generate command acknowledge signal
                   cmd_ack  <=  1'b1;
                end
 
          endcase
       end
endmodule

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[/] [openrisc/] [trunk/] [orpsocv2/] [rtl/] [verilog/] [i2c_master_slave/] [i2c_master_byte_ctrl.v] - Blame information for rev 501

Line No.	Rev	Author	Line
1	408	julius	`/////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// WISHBONE rev.B2 compliant I2C Master byte-controller ////`
4			`//// ////`
5			`//// ////`
6			`//// Author: Richard Herveille ////`
7			`//// richard@asics.ws ////`
8			`//// www.asics.ws ////`
9			`//// ////`
10			`//// Downloaded from: http://www.opencores.org/projects/i2c/ ////`
11			`//// ////`
12			`/////////////////////////////////////////////////////////////////////`
13			`//// ////`
14			`//// Copyright (C) 2001 Richard Herveille ////`
15			`//// richard@asics.ws ////`
16			`//// ////`
17			`//// This source file may be used and distributed without ////`
18			`//// restriction provided that this copyright statement is not ////`
19			`//// removed from the file and that any derivative work contains ////`
20			`//// the original copyright notice and the associated disclaimer.////`
21			`//// ////`
22			//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
23			`//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////`
24			`//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////`
25			`//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////`
26			`//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////`
27			`//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////`
28			`//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////`
29			`//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////`
30			`//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////`
31			`//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////`
32			`//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////`
33			`//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////`
34			`//// POSSIBILITY OF SUCH DAMAGE. ////`
35			`//// ////`
36			`/////////////////////////////////////////////////////////////////////`
37
38			`// CVS Log`
39			`//`
40			`// $Id: i2c_master_byte_ctrl.v,v 1.8 2009-01-19 20:29:26 rherveille Exp $`
41			`//`
42			`// $Date: 2009-01-19 20:29:26 $`
43			`// $Revision: 1.8 $`
44			`// $Author: rherveille $`
45			`// $Locker: $`
46			`// $State: Exp $`
47			`//`
48			`// Change History:`
49			`// $Log: not supported by cvs2svn $`
50			`// Revision 1.7 2004/02/18 11:40:46 rherveille`
51			`// Fixed a potential bug in the statemachine. During a 'stop' 2 cmd_ack signals were generated. Possibly canceling a new start command.`
52			`//`
53			`// Revision 1.6 2003/08/09 07:01:33 rherveille`
54			`// Fixed a bug in the Arbitration Lost generation caused by delay on the (external) sda line.`
55			`// Fixed a potential bug in the byte controller's host-acknowledge generation.`
56			`//`
57			`// Revision 1.5 2002/12/26 15:02:32 rherveille`
58			`// Core is now a Multimaster I2C controller`
59			`//`
60			`// Revision 1.4 2002/11/30 22:24:40 rherveille`
61			`// Cleaned up code`
62			`//`
63			`// Revision 1.3 2001/11/05 11:59:25 rherveille`
64			`// Fixed wb_ack_o generation bug.`
65			`// Fixed bug in the byte_controller statemachine.`
66			`// Added headers.`
67			`//`
68
69			`// synopsys translate_off`
70			`include "timescale.v"
71			`// synopsys translate_on`
72
73			`include "i2c_master_slave_defines.v"
74
75			`module i2c_master_byte_ctrl`
76			`(`
77			`clk, my_addr, rst, nReset, ena, clk_cnt, start, stop, read, write, ack_in,`
78			`din, cmd_ack, ack_out, dout, i2c_busy, i2c_al, scl_i, sl_cont, scl_o,`
79			`scl_oen, sda_i, sda_o, sda_oen,slave_dat_req, slave_en, slave_dat_avail,`
80			`slave_act, slave_cmd_ack`
81			`);`
82
83
84			`//`
85			`// inputs & outputs`
86			`//`
87			`input clk; // master clock`
88			`input my_addr; // Slave address input`
89			`input rst; // synchronous active high reset`
90			`input nReset; // asynchronous active low reset`
91			`input ena; // core enable signal`
92			`input sl_cont;`
93			`input [15:0] clk_cnt; // 4x SCL`
94
95			`// control inputs`
96			`input start;`
97			`input stop;`
98			`input read;`
99			`input write;`
100			`input ack_in;`
101			`input [7:0] din;`
102
103			`// status outputs`
104			`output cmd_ack;`
105			`reg cmd_ack;`
106			`output ack_out;`
107			`reg ack_out;`
108			`output i2c_busy;`
109			`output i2c_al;`
110			`output [7:0] dout;`
111
112			`// I2C signals`
113			`input scl_i;`
114			`output scl_o;`
115			`output scl_oen;`
116			`input sda_i;`
117			`output sda_o;`
118			`output sda_oen;`
119			`input slave_en;`
120			`output reg slave_dat_req;`
121			`output reg slave_dat_avail;`
122			`output reg slave_act;`
123			`output reg slave_cmd_ack;`
124			`//`
125			`// Variable declarations`
126			`//`
127
128			`// statemachine`
129			`parameter [9:0] ST_IDLE = 10'b00_0000_0000;`
130			`parameter [9:0] ST_START = 10'b00_0000_0001;`
131			`parameter [9:0] ST_READ = 10'b00_0000_0010;`
132			`parameter [9:0] ST_WRITE = 10'b00_0000_0100;`
133			`parameter [9:0] ST_ACK = 10'b00_0000_1000;`
134			`parameter [9:0] ST_STOP = 10'b00_0001_0000;`
135			`parameter [9:0] ST_SL_ACK = 10'b00_0010_0000;`
136			`parameter [9:0] ST_SL_RD = 10'b00_0100_0000;`
137			`parameter [9:0] ST_SL_WR = 10'b00_1000_0000;`
138			`parameter [9:0] ST_SL_WAIT = 10'b01_0000_0000;`
139			`parameter [9:0] ST_SL_PRELOAD = 10'b10_0000_0000;`
140
141
142			`reg sl_wait;`
143			`// signals for bit_controller`
144			`wire [6:0] my_addr;`
145			`reg [3:0] core_cmd;`
146			`reg core_txd;`
147			`wire core_ack, core_rxd;`
148			`wire sl_cont;`
149			`// signals for shift register`
150			`reg [7:0] sr; //8bit shift register`
151			`reg shift, ld;`
152			`reg master_mode;`
153			`reg [1:0] slave_cmd_out;`
154			`// signals for state machine`
155			`wire go;`
156			`reg [2:0] dcnt;`
157			`wire cnt_done;`
158			`wire slave_ack;`
159
160
161			`//Slave signals`
162			`wire slave_adr_received;`
163			`wire [7:0] slave_adr;`
164
165
166			`reg [1:0] slave_cmd;`
167			`//`
168			`// Module body`
169			`//`
170
171			`// hookup bit_controller`
172			`i2c_master_bit_ctrl bit_controller`
173			`(`
174			`.clk ( clk ),`
175			`.rst ( rst ),`
176			`.nReset ( nReset ),`
177			`.ena ( ena ),`
178			`.clk_cnt ( clk_cnt ),`
179			`.cmd ( core_cmd ),`
180			`.cmd_ack ( core_ack ),`
181			`.busy ( i2c_busy ),`
182			`.al ( i2c_al ),`
183			`.din ( core_txd ),`
184			`.dout ( core_rxd ),`
185			`.scl_i ( scl_i ),`
186			`.scl_o ( scl_o ),`
187			`.scl_oen ( scl_oen ),`
188			`.sda_i ( sda_i ),`
189			`.sda_o ( sda_o ),`
190			`.sda_oen ( sda_oen ),`
191			`.slave_adr_received ( slave_adr_received ),`
192			`.slave_adr ( slave_adr ),`
193			`.master_mode (master_mode),`
194			`.cmd_slave_ack (slave_ack),`
195			`.slave_cmd (slave_cmd_out),`
196			`.sl_wait (sl_wait),`
197			`.slave_reset (slave_reset)`
198			`);`
199
200			`reg slave_adr_received_d;`
201			`// generate go-signal`
202			`assign go = (read \| write \| stop) & ~cmd_ack;`
203
204			`// assign dout output to shift-register`
205			`assign dout = sr;`
206
207			`always @(posedge clk or negedge nReset)`
208			`if (!nReset)`
209			`slave_adr_received_d <= 1'b0;`
210			`else`
211			`slave_adr_received_d <= slave_adr_received;`
212
213			`// generate shift register`
214			`always @(posedge clk or negedge nReset)`
215			`if (!nReset)`
216			`sr <= 8'h0;`
217			`else if (rst)`
218			`sr <= 8'h0;`
219			`else if (ld)`
220			`sr <= din;`
221			`else if (shift)`
222			`sr <= {sr[6:0], core_rxd};`
223			`else if (slave_adr_received_d & slave_act)`
224			`sr <= {slave_adr[7:1], 1'b0};`
225
226
227
228			`// generate counter`
229			`always @(posedge clk or negedge nReset)`
230			`if (!nReset)`
231			`dcnt <= 3'h0;`
232			`else if (rst)`
233			`dcnt <= 3'h0;`
234			`else if (ld)`
235			`dcnt <= 3'h7;`
236
237			`else if (shift)`
238			`dcnt <= dcnt - 3'h1;`
239
240			`assign cnt_done = ~(\|dcnt);`
241
242			`//`
243			`// state machine`
244			`//`
245			`reg [9:0] c_state; // synopsys enum_state`
246
247
248
249			`always @(posedge clk or negedge nReset)`
250			`if (!nReset)`
251			`begin`
252			`sl_wait <= 1'b0;`
253			core_cmd <= `I2C_CMD_NOP;
254			`core_txd <= 1'b0;`
255			`shift <= 1'b0;`
256			`ld <= 1'b0;`
257			`cmd_ack <= 1'b0;`
258			`c_state <= ST_IDLE;`
259			`ack_out <= 1'b0;`
260			`master_mode <= 1'b0;`
261			`slave_cmd <= 2'b0;`
262			`slave_dat_req <= 1'b0;`
263			`slave_dat_avail <= 1'b0;`
264			`slave_act <= 1'b0;`
265			`slave_cmd_out <= 2'b0;`
266			`slave_cmd_ack <= 1'b0;`
267			`end`
268			`else if (rst \| i2c_al \| slave_reset)`
269			`begin`
270			core_cmd <= `I2C_CMD_NOP;
271			`core_txd <= 1'b0;`
272			`shift <= 1'b0;`
273			`sl_wait <= 1'b0;`
274			`ld <= 1'b0;`
275			`cmd_ack <= 1'b0;`
276			`c_state <= ST_IDLE;`
277			`ack_out <= 1'b0;`
278			`master_mode <= 1'b0;`
279			`slave_cmd <= 2'b0;`
280			`slave_cmd_out <= 2'b0;`
281			`slave_dat_req <= 1'b0;`
282			`slave_dat_avail <= 1'b0;`
283			`slave_act <= 1'b0;`
284			`slave_cmd_ack <= 1'b0;`
285			`end`
286			`else`
287			`begin`
288			`slave_cmd_out <= slave_cmd;`
289			`// initially reset all signals`
290			`core_txd <= sr[7];`
291			`shift <= 1'b0;`
292			`ld <= 1'b0;`
293			`cmd_ack <= 1'b0;`
294			`slave_cmd_ack <= 1'b0;`
295
296			`case (c_state) // synopsys full_case parallel_case`
297			`ST_IDLE:`
298			`begin`
299			`slave_act <= 1'b0;`
300			`if (slave_en & slave_adr_received &`
301			`(slave_adr[7:1] == my_addr )) begin`
302
303			`c_state <= ST_SL_ACK;`
304			`master_mode <= 1'b0;`
305			`slave_act <= 1'b1;`
306			slave_cmd <= `I2C_SLAVE_CMD_WRITE;
307			`core_txd <= 1'b0;`
308
309			`end`
310			`else if (go && !slave_act )`
311			`begin`
312			`if (start )`
313			`begin`
314			`c_state <= ST_START;`
315			core_cmd <= `I2C_CMD_START;
316			`master_mode <= 1'b1;`
317			`end`
318			`else if (read)`
319			`begin`
320			`c_state <= ST_READ;`
321			core_cmd <= `I2C_CMD_READ;
322			`end`
323			`else if (write)`
324			`begin`
325			`c_state <= ST_WRITE;`
326			core_cmd <= `I2C_CMD_WRITE;
327			`end`
328			`else // stop`
329			`begin`
330			`c_state <= ST_STOP;`
331			core_cmd <= `I2C_CMD_STOP;
332
333			`end`
334
335			`ld <= 1'b1;`
336			`end`
337
338			`end`
339			`ST_SL_RD: //If master read, slave sending data`
340			`begin`
341			slave_cmd <= `I2C_SLAVE_CMD_NOP;
342			`if (slave_ack) begin`
343			`if (cnt_done) begin`
344			`c_state <= ST_SL_ACK;`
345			slave_cmd <= `I2C_SLAVE_CMD_READ;
346			`end`
347			`else`
348			`begin`
349			`c_state <= ST_SL_RD;`
350			slave_cmd <= `I2C_SLAVE_CMD_WRITE;
351			`shift <= 1'b1;`
352			`end`
353			`end`
354			`end`
355			`ST_SL_WR: //If master write, slave reading data`
356			`begin`
357			slave_cmd <= `I2C_SLAVE_CMD_NOP;
358			`if (slave_ack)`
359			`begin`
360			`if (cnt_done)`
361			`begin`
362			`c_state <= ST_SL_ACK;`
363			slave_cmd <= `I2C_SLAVE_CMD_WRITE;
364			`core_txd <= 1'b0;`
365			`end`
366			`else`
367			`begin`
368			`c_state <= ST_SL_WR;`
369			slave_cmd <= `I2C_SLAVE_CMD_READ;
370			`end`
371			`shift <= 1'b1;`
372			`end`
373			`end`
374			`ST_SL_WAIT: //Wait for interupt-clear and hold SCL in waitstate`
375			`begin`
376			`sl_wait <= 1'b1;`
377			`if (sl_cont) begin`
378			`sl_wait <= 1'b0;`
379			`ld <= 1'b1;`
380			`slave_dat_req <= 1'b0;`
381			`slave_dat_avail <= 1'b0;`
382			`c_state <= ST_SL_PRELOAD;`
383			`end`
384			`end`
385
386			`ST_SL_PRELOAD:`
387			`if (slave_adr[0]) begin`
388			`c_state <= ST_SL_RD;`
389			slave_cmd <= `I2C_SLAVE_CMD_WRITE;
390			`end`
391			`else begin`
392			`c_state <= ST_SL_WR;`
393			slave_cmd <= `I2C_SLAVE_CMD_READ;
394			`end`
395
396			`ST_SL_ACK:`
397			`begin`
398			slave_cmd <= `I2C_SLAVE_CMD_NOP;
399			`if (slave_ack) begin`
400			`ack_out <= core_rxd;`
401			`slave_cmd_ack <= 1'b1;`
402			`if (!core_rxd) begin // Valid ack recived`
403			`// generate slave command acknowledge signal if`
404			`// succesful transfer`
405			`c_state <= ST_SL_WAIT;`
406			`if (slave_adr[0]) begin // I2C read request`
407			`slave_dat_req <= 1'b1;`
408			`end`
409			`else begin // I2C write request`
410			`slave_dat_avail <= 1'b1;`
411			`end`
412			`end`
413			`else begin`
414			`c_state <= ST_IDLE;`
415			`end`
416			`end`
417			`else begin`
418			`core_txd <= 1'b0;`
419			`end`
420			`end`
421
422			`ST_START:`
423			`if (core_ack)`
424			`begin`
425			`if (read)`
426			`begin`
427			`c_state <= ST_READ;`
428			core_cmd <= `I2C_CMD_READ;
429			`end`
430			`else`
431			`begin`
432			`c_state <= ST_WRITE;`
433			core_cmd <= `I2C_CMD_WRITE;
434			`end`
435
436			`ld <= 1'b1;`
437			`end`
438
439			`ST_WRITE:`
440			`if (core_ack)`
441			`if (cnt_done)`
442			`begin`
443			`c_state <= ST_ACK;`
444			core_cmd <= `I2C_CMD_READ;
445			`end`
446			`else`
447			`begin`
448			`c_state <= ST_WRITE; // stay in same state`
449			core_cmd <= `I2C_CMD_WRITE; // write next bit
450			`shift <= 1'b1;`
451			`end`
452
453			`ST_READ:`
454			`if (core_ack)`
455			`begin`
456			`if (cnt_done)`
457			`begin`
458			`c_state <= ST_ACK;`
459			core_cmd <= `I2C_CMD_WRITE;
460			`end`
461			`else`
462			`begin`
463			`c_state <= ST_READ; // stay in same state`
464			core_cmd <= `I2C_CMD_READ; // read next bit
465			`end`
466
467			`shift <= 1'b1;`
468			`core_txd <= ack_in;`
469			`end`
470
471			`ST_ACK:`
472			`if (core_ack)`
473			`begin`
474			`if (stop)`
475			`begin`
476			`c_state <= ST_STOP;`
477			core_cmd <= `I2C_CMD_STOP;
478			`end`
479			`else`
480			`begin`
481			`c_state <= ST_IDLE;`
482			core_cmd <= `I2C_CMD_NOP;
483
484			`// generate command acknowledge signal`
485			`cmd_ack <= 1'b1;`
486			`end`
487
488			`// assign ack_out output to bit_controller_rxd (contains`
489			`// last received bit)`
490			`ack_out <= core_rxd;`
491
492			`core_txd <= 1'b1;`
493			`end`
494			`else`
495			`core_txd <= ack_in;`
496
497			`ST_STOP:`
498			`if (core_ack)`
499			`begin`
500			`c_state <= ST_IDLE;`
501			core_cmd <= `I2C_CMD_NOP;
502
503			`// generate command acknowledge signal`
504			`cmd_ack <= 1'b1;`
505			`end`
506
507			`endcase`
508			`end`
509			`endmodule`