Add multichannel and sample rate accurate version

source/dual_mcp3201_pmod.sv

@@ -1,8 +1,10 @@
 `timescale 1ns/100ps
 `default_nettype none
 
+`define MULTICHANNEL_VERSION
+
 module dual_mcp3201_pmod #(parameter CLOCK_FREQ = 25000000,
-             parameter SAMPLE_RATE = 50000)
+                           parameter SAMPLE_RATE = 50000)
     (input wire clock,
      input wire reset,
 
@@ -19,6 +21,29 @@ module dual_mcp3201_pmod #(parameter CLOCK_FREQ = 25000000,
      output wire [11:0] ldata,
      output wire        lstrb);
 
+`ifdef MULTICHANNEL_VERSION
+    /* Multichannel and sample rate accurate version */
+
+    localparam SPI_SCLK_FREQ = 1000000;
+
+    mcp3201_ma #(.CHANNELS(2),
+                 .CLOCK_FREQ(CLOCK_FREQ),
+                 .SCLK_FREQ(SPI_SCLK_FREQ),
+                 .SAMPLE_RATE(SAMPLE_RATE)) adcs
+      (.clock, .reset,
+       .spi_clk_o(radc_clk),
+       .spi_ssn_o(radc_ssn),
+       .spi_miso_i({ radc_dat, ladc_dat }),
+       .data_o({ rdata, ldata }),
+       .strb_o(rstrb));
+
+    assign ladc_clk = radc_clk;
+    assign ladc_ssn = radc_ssn;
+    assign lstrb = rstrb;
+
+`else
+    /* Single channel inaccurate version */
+
     localparam MCP3201_CLOCK_PER_SAMPLE = 17;
     localparam SCLK_FREQ = SAMPLE_RATE * MCP3201_CLOCK_PER_SAMPLE;
 
@@ -47,5 +72,6 @@ module dual_mcp3201_pmod #(parameter CLOCK_FREQ = 25000000,
 
     assign ladc_clk = spi_clk;
     assign radc_clk = spi_clk;
+`endif
 
 endmodule // dual_mcp3201_pmod

source/mcp3201_ma.sv

@@ -0,0 +1,131 @@
+`timescale 1ns/100ps
+`default_nettype none
+
+/*
+ * MCP3201 controller
+ * Multichannel and sample rate accurate version.
+ */
+module mcp3201_ma #(parameter CHANNELS = 1,
+                    parameter CLOCK_FREQ = 12000000,
+                    parameter SCLK_FREQ = 1000000,
+                    parameter SAMPLE_RATE = 44100)
+    (input wire clock,
+     input wire reset,
+
+     output reg spi_clk_o,
+     output reg spi_ssn_o,
+     input wire [CHANNELS-1:0] spi_miso_i,
+
+     output reg [CHANNELS*12-1:0] data_o,
+     output reg strb_o);
+
+    initial
+      if (CHANNELS < 1)
+        $error("Channels count must be > 1");
+
+    /* SCLK frequency not need accuracy */
+    localparam SCLK_PERIOD = CLOCK_FREQ/SCLK_FREQ;
+    localparam SCLK_CW = $clog2(SCLK_PERIOD);
+
+    logic [SCLK_CW-1:0] sclk_cnt;
+    logic sclk_posedge;
+
+    /* Make SPI SCLK */
+    always_ff @(posedge clock)
+      if (reset | spi_ssn_o) begin
+          spi_clk_o    <= 1'b1;
+          sclk_cnt     <= '0;
+          sclk_posedge <= 1'b0;
+      end
+      else begin
+          sclk_posedge <= 1'b0;
+          sclk_cnt <= sclk_cnt + 1'b1;
+
+          if (sclk_cnt == SCLK_CW'(SCLK_PERIOD/2))
+            spi_clk_o <= 1'b0;
+          else
+            if (sclk_cnt == SCLK_CW'(SCLK_PERIOD-1)) begin
+                spi_clk_o    <= 1'b1;
+                sclk_cnt     <= '0;
+                sclk_posedge <= 1'b1;
+            end
+      end
+
+    /* Sample rate need more accuracy */
+    localparam SRATE_PERIOD = integer'($floor(real'(CLOCK_FREQ)/real'(SAMPLE_RATE) + 0.5));
+    localparam SRATE_CW = $clog2(SRATE_PERIOD);
+
+    logic [SRATE_CW-1:0] srate_cnt;
+    logic sample;
+
+    always_ff @(posedge clock)
+      if (reset) begin
+          sample    <= 1'b0;
+          srate_cnt <= '0;
+      end
+      else
+        if (srate_cnt == SRATE_CW'(SRATE_PERIOD-1)) begin
+            sample    <= 1'b1;
+            srate_cnt <= '0;
+        end
+        else begin
+            sample    <= 1'b0;
+            srate_cnt <= srate_cnt + 1'b1;
+        end
+
+    /* Receive data FSM */
+    enum int unsigned {
+        ST_RELAX = 0,
+        ST_SHIFT,
+        ST_STROBE
+    } state;
+
+    logic [3:0] bit_cnt;
+    logic [11:0] data_sr[CHANNELS];
+
+    always_ff @(posedge clock)
+      if (reset) begin
+          state     <= ST_RELAX;
+          bit_cnt   <= '0;
+          spi_ssn_o <= 1'b1;
+          strb_o    <= 1'b0;
+          data_o    <= '0;
+
+          for (int i = 0; i < CHANNELS; i ++)
+            data_sr[i] <= '0;
+      end
+      else begin
+          strb_o <= 1'b0;
+
+          case (state)
+            ST_RELAX:
+              if (sample) begin
+                  bit_cnt   <= '0;
+                  spi_ssn_o <= 1'b0;
+                  state     <= ST_SHIFT;
+              end
+
+            ST_SHIFT:
+              if (sclk_posedge) begin
+                  for (int i = 0; i < CHANNELS; i ++)
+                    data_sr[i] <= { data_sr[i][10:0], spi_miso_i[i] };
+
+                  bit_cnt <= bit_cnt + 1'b1;
+
+                  if (bit_cnt == 4'd14) begin
+                      spi_ssn_o <= 1'b1;
+                      state <= ST_STROBE;
+                  end
+              end
+
+            ST_STROBE: begin
+                for (int i = 0; i < CHANNELS; i ++)
+                  data_o[i*12 +: 12] <= data_sr[i];
+
+                strb_o <= 1'b1;
+                state  <= ST_RELAX;
+            end
+          endcase
+      end
+
+endmodule // mcp3201_ma