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/////////////////////////////////////////////////////////////////////
////                                                             ////
////  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 1.6 2002-11-30 22:24:40 rherveille Exp $
//
//  $Date: 2002-11-30 22:24:40 $
//  $Revision: 1.6 $
//  $Author: rherveille $
//  $Locker:  $
//  $State: Exp $
//
// Change History:
//               $Log: not supported by cvs2svn $
//               Revision 1.5  2001/11/10 10:52:55  rherveille
//               Changed PRER reset value from 0x0000 to 0xffff, conform specs.
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
 
`include "i2c_master_defines.v"
 
module i2c_master_top(
        wb_clk_i, wb_rst_i, arst_i, wb_adr_i, wb_dat_i, wb_dat_o,
        wb_we_i, wb_stb_i, wb_cyc_i, wb_ack_o, wb_inta_o,
        scl_pad_i, scl_pad_o, scl_padoen_o, sda_pad_i, sda_pad_o, sda_padoen_o );
 
        // parameters
        parameter ARST_LVL = 1'b0; // asynchronous reset level
 
        //
        // inputs & outputs
        //
 
        // wishbone signals
        input        wb_clk_i;     // master clock input
        input        wb_rst_i;     // synchronous active high reset
        input        arst_i;       // asynchronous reset
        input  [2:0] wb_adr_i;     // lower address bits
        input  [7:0] wb_dat_i;     // databus input
        output [7:0] wb_dat_o;     // databus output
        input        wb_we_i;      // write enable input
        input        wb_stb_i;     // stobe/core select signal
        input        wb_cyc_i;     // valid bus cycle input
        output       wb_ack_o;     // bus cycle acknowledge output
        output       wb_inta_o;    // interrupt request signal output
 
        reg [7:0] wb_dat_o;
        reg wb_ack_o;
        reg wb_inta_o;
 
        // I2C signals
        // i2c clock line
        input  scl_pad_i;       // SCL-line input
        output scl_pad_o;       // SCL-line output (always 1'b0)
        output scl_padoen_o;    // SCL-line output enable (active low)
 
        // i2c data line
        input  sda_pad_i;       // SDA-line input
        output sda_pad_o;       // SDA-line output (always 1'b0)
        output sda_padoen_o;    // SDA-line output enable (active low)
 
 
        //
        // variable declarations
        //
 
        // registers
        reg  [15:0] prer; // clock prescale register
        reg  [ 7:0] ctr;  // control register
        reg  [ 7:0] txr;  // transmit register
        wire [ 7:0] rxr;  // receive register
        reg  [ 7:0] cr;   // command register
        wire [ 7:0] sr;   // status register
 
        // done signal: command completed, clear command register
        wire done;
 
        // core enable signal
        wire core_en;
        wire ien;
 
        // status register signals
        wire irxack;
        reg  rxack;       // received aknowledge from slave
        reg  tip;         // transfer in progress
        reg  irq_flag;    // interrupt pending flag
        wire i2c_busy;    // bus busy (start signal detected)
 
        //
        // module body
        //
 
        // generate internal reset
        wire rst_i = arst_i ^ ARST_LVL;
 
        // generate acknowledge output signal
        always @(posedge wb_clk_i)
          wb_ack_o <= #1 wb_cyc_i & wb_stb_i & ~wb_ack_o; // because timing is always honored
 
        // assign DAT_O
        always @(posedge wb_clk_i)
        begin
          case (wb_adr_i) // synopsis full_case parallel_case
            3'b000: wb_dat_o = prer[ 7:0];
            3'b001: wb_dat_o = prer[15:8];
            3'b010: wb_dat_o = ctr;
            3'b011: wb_dat_o = rxr; // write is transmit register (txr)
            3'b100: wb_dat_o = sr;  // write is command register (cr)
            3'b101: wb_dat_o = txr;
            3'b110: wb_dat_o = cr;
            3'b111: wb_dat_o = 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;
                cr   <= #1  8'h0;
            end
          else if (wb_rst_i)
            begin
                prer <= #1 16'hffff;
                ctr  <= #1  8'h0;
                txr  <= #1  8'h0;
                cr   <= #1  8'h0;
            end
          else
            if (wb_cyc_i && wb_stb_i && wb_we_i)
              begin
                  if (!wb_adr_i[2])
                    case (wb_adr_i[1:0]) // synopsis full_case parallel_case
                      2'b00 : prer [ 7:0] <= #1 wb_dat_i;
                      2'b01 : prer [15:8] <= #1 wb_dat_i;
                      2'b10 : ctr         <= #1 wb_dat_i;
                      2'b11 : txr         <= #1 wb_dat_i;
                    endcase
                  else
                    if (core_en && (wb_adr_i[1:0] == 2'b00) ) // only take new commands when i2c core enabled, pending commands are finished
                      cr <= #1 wb_dat_i;
              end
            else
              begin
                  if (done)
                    cr[7:4] <= #1 4'h0; // clear command bits when done
 
                  cr[2:1] <= #1 2'b00;  // reserved bits
                  cr[0]   <= #1 cr[0] && irq_flag; // clear when irq_flag cleared
              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     ),
                .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
                rxack    <= #1 1'b0;
                tip      <= #1 1'b0;
                irq_flag <= #1 1'b0;
            end
          else if (wb_rst_i)
            begin
                rxack    <= #1 1'b0;
                tip      <= #1 1'b0;
                irq_flag <= #1 1'b0;
            end
          else
            begin
                rxack    <= #1 irxack;
                tip      <= #1 (rd | wr);
                irq_flag <= #1 (done | 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[5:2] = 4'h0; // reserved
        assign sr[1]   = tip;
        assign sr[0]   = irq_flag;
 
endmodule

Line No.	Rev	Author	Line
1	14	rherveille	`/////////////////////////////////////////////////////////////////////`
2			`//// ////`
3	27	rherveille	`//// WISHBONE revB.2 compliant I2C Master controller Top-level ////`
4	14	rherveille	`//// ////`
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	10	rherveille	`//`
40	27	rherveille	`// $Id: i2c_master_top.v,v 1.6 2002-11-30 22:24:40 rherveille Exp $`
41	10	rherveille	`//`
42	27	rherveille	`// $Date: 2002-11-30 22:24:40 $`
43			`// $Revision: 1.6 $`
44	14	rherveille	`// $Author: rherveille $`
45			`// $Locker: $`
46			`// $State: Exp $`
47	10	rherveille	`//`
48	14	rherveille	`// Change History:`
49			`// $Log: not supported by cvs2svn $`
50	27	rherveille	`// Revision 1.5 2001/11/10 10:52:55 rherveille`
51			`// Changed PRER reset value from 0x0000 to 0xffff, conform specs.`
52			`//`
53	10	rherveille
54	27	rherveille	`// synopsys translate_off`
55	10	rherveille	`include "timescale.v"
56	27	rherveille	`// synopsys translate_on`
57
58	10	rherveille	`include "i2c_master_defines.v"
59
60			`module i2c_master_top(`
61			`wb_clk_i, wb_rst_i, arst_i, wb_adr_i, wb_dat_i, wb_dat_o,`
62			`wb_we_i, wb_stb_i, wb_cyc_i, wb_ack_o, wb_inta_o,`
63			`scl_pad_i, scl_pad_o, scl_padoen_o, sda_pad_i, sda_pad_o, sda_padoen_o );`
64
65	11	rherveille	`// parameters`
66			`parameter ARST_LVL = 1'b0; // asynchronous reset level`
67
68	10	rherveille	`//`
69			`// inputs & outputs`
70			`//`
71
72			`// wishbone signals`
73			`input wb_clk_i; // master clock input`
74			`input wb_rst_i; // synchronous active high reset`
75			`input arst_i; // asynchronous reset`
76			`input [2:0] wb_adr_i; // lower address bits`
77			`input [7:0] wb_dat_i; // databus input`
78			`output [7:0] wb_dat_o; // databus output`
79			`input wb_we_i; // write enable input`
80			`input wb_stb_i; // stobe/core select signal`
81			`input wb_cyc_i; // valid bus cycle input`
82			`output wb_ack_o; // bus cycle acknowledge output`
83			`output wb_inta_o; // interrupt request signal output`
84	27	rherveille
85			`reg [7:0] wb_dat_o;`
86			`reg wb_ack_o;`
87	10	rherveille	`reg wb_inta_o;`
88
89			`// I2C signals`
90			`// i2c clock line`
91			`input scl_pad_i; // SCL-line input`
92			`output scl_pad_o; // SCL-line output (always 1'b0)`
93			`output scl_padoen_o; // SCL-line output enable (active low)`
94	27	rherveille
95	10	rherveille	`// i2c data line`
96			`input sda_pad_i; // SDA-line input`
97			`output sda_pad_o; // SDA-line output (always 1'b0)`
98			`output sda_padoen_o; // SDA-line output enable (active low)`
99
100
101			`//`
102			`// variable declarations`
103			`//`
104
105			`// registers`
106			`reg [15:0] prer; // clock prescale register`
107			`reg [ 7:0] ctr; // control register`
108			`reg [ 7:0] txr; // transmit register`
109			`wire [ 7:0] rxr; // receive register`
110			`reg [ 7:0] cr; // command register`
111			`wire [ 7:0] sr; // status register`
112
113			`// done signal: command completed, clear command register`
114			`wire done;`
115
116			`// core enable signal`
117			`wire core_en;`
118	13	rherveille	`wire ien;`
119	10	rherveille
120			`// status register signals`
121			`wire irxack;`
122			`reg rxack; // received aknowledge from slave`
123			`reg tip; // transfer in progress`
124			`reg irq_flag; // interrupt pending flag`
125			`wire i2c_busy; // bus busy (start signal detected)`
126
127			`//`
128			`// module body`
129			`//`
130
131			`// generate internal reset`
132	11	rherveille	`wire rst_i = arst_i ^ ARST_LVL;`
133	27	rherveille
134	10	rherveille	`// generate acknowledge output signal`
135	27	rherveille	`always @(posedge wb_clk_i)`
136			`wb_ack_o <= #1 wb_cyc_i & wb_stb_i & ~wb_ack_o; // because timing is always honored`
137	10	rherveille
138			`// assign DAT_O`
139	27	rherveille	`always @(posedge wb_clk_i)`
140	10	rherveille	`begin`
141	27	rherveille	`case (wb_adr_i) // synopsis full_case parallel_case`
142			`3'b000: wb_dat_o = prer[ 7:0];`
143			`3'b001: wb_dat_o = prer[15:8];`
144			`3'b010: wb_dat_o = ctr;`
145			`3'b011: wb_dat_o = rxr; // write is transmit register (txr)`
146			`3'b100: wb_dat_o = sr; // write is command register (cr)`
147			`3'b101: wb_dat_o = txr;`
148			`3'b110: wb_dat_o = cr;`
149			`3'b111: wb_dat_o = 0; // reserved`
150			`endcase`
151	10	rherveille	`end`
152
153
154			`// generate registers`
155	27	rherveille	`always @(posedge wb_clk_i or negedge rst_i)`
156			`if (!rst_i)`
157			`begin`
158			`prer <= #1 16'hffff;`
159			`ctr <= #1 8'h0;`
160			`txr <= #1 8'h0;`
161			`cr <= #1 8'h0;`
162			`end`
163			`else if (wb_rst_i)`
164			`begin`
165			`prer <= #1 16'hffff;`
166			`ctr <= #1 8'h0;`
167			`txr <= #1 8'h0;`
168			`cr <= #1 8'h0;`
169			`end`
170			`else`
171			`if (wb_cyc_i && wb_stb_i && wb_we_i)`
172			`begin`
173			`if (!wb_adr_i[2])`
174			`case (wb_adr_i[1:0]) // synopsis full_case parallel_case`
175			`2'b00 : prer [ 7:0] <= #1 wb_dat_i;`
176			`2'b01 : prer [15:8] <= #1 wb_dat_i;`
177			`2'b10 : ctr <= #1 wb_dat_i;`
178			`2'b11 : txr <= #1 wb_dat_i;`
179			`endcase`
180			`else`
181			`if (core_en && (wb_adr_i[1:0] == 2'b00) ) // only take new commands when i2c core enabled, pending commands are finished`
182			`cr <= #1 wb_dat_i;`
183			`end`
184			`else`
185			`begin`
186			`if (done)`
187			`cr[7:4] <= #1 4'h0; // clear command bits when done`
188	10	rherveille
189	27	rherveille	`cr[2:1] <= #1 2'b00; // reserved bits`
190			`cr[0] <= #1 cr[0] && irq_flag; // clear when irq_flag cleared`
191			`end`
192	10	rherveille
193
194			`// decode command register`
195			`wire sta = cr[7];`
196			`wire sto = cr[6];`
197			`wire rd = cr[5];`
198			`wire wr = cr[4];`
199			`wire ack = cr[3];`
200			`wire iack = cr[0];`
201
202			`// decode control register`
203			`assign core_en = ctr[7];`
204	13	rherveille	`assign ien = ctr[6];`
205	10	rherveille
206			`// hookup byte controller block`
207			`i2c_master_byte_ctrl byte_controller (`
208	27	rherveille	`.clk ( wb_clk_i ),`
209			`.rst ( wb_rst_i ),`
210			`.nReset ( rst_i ),`
211			`.ena ( core_en ),`
212			`.clk_cnt ( prer ),`
213			`.start ( sta ),`
214			`.stop ( sto ),`
215			`.read ( rd ),`
216			`.write ( wr ),`
217			`.ack_in ( ack ),`
218			`.din ( txr ),`
219			`.cmd_ack ( done ),`
220			`.ack_out ( irxack ),`
221			`.dout ( rxr ),`
222			`.i2c_busy ( i2c_busy ),`
223			`.scl_i ( scl_pad_i ),`
224			`.scl_o ( scl_pad_o ),`
225			`.scl_oen ( scl_padoen_o ),`
226			`.sda_i ( sda_pad_i ),`
227			`.sda_o ( sda_pad_o ),`
228			`.sda_oen ( sda_padoen_o )`
229	10	rherveille	`);`
230
231
232			`// status register block + interrupt request signal`
233	27	rherveille	`always @(posedge wb_clk_i or negedge rst_i)`
234			`if (!rst_i)`
235			`begin`
236			`rxack <= #1 1'b0;`
237			`tip <= #1 1'b0;`
238			`irq_flag <= #1 1'b0;`
239			`end`
240			`else if (wb_rst_i)`
241			`begin`
242			`rxack <= #1 1'b0;`
243			`tip <= #1 1'b0;`
244			`irq_flag <= #1 1'b0;`
245			`end`
246			`else`
247			`begin`
248			`rxack <= #1 irxack;`
249			`tip <= #1 (rd \| wr);`
250			`irq_flag <= #1 (done \| irq_flag) & ~iack; // interrupt request flag is always generated`
251			`end`
252	10	rherveille
253	27	rherveille	`// generate interrupt request signals`
254			`always @(posedge wb_clk_i or negedge rst_i)`
255			`if (!rst_i)`
256			`wb_inta_o <= #1 1'b0;`
257			`else if (wb_rst_i)`
258			`wb_inta_o <= #1 1'b0;`
259			`else`
260			`wb_inta_o <= #1 irq_flag && ien; // interrupt signal is only generated when IEN (interrupt enable bit is set)`
261	10	rherveille
262	27	rherveille	`// assign status register bits`
263			`assign sr[7] = rxack;`
264			`assign sr[6] = i2c_busy;`
265			`assign sr[5:2] = 4'h0; // reserved`
266			`assign sr[1] = tip;`
267			`assign sr[0] = irq_flag;`
268	10	rherveille
269			`endmodule`

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[/] [i2c/] [trunk/] [rtl/] [verilog/] [i2c_master_top.v] - Blame information for rev 27