Correctly read single-byte incoming transmissions (PC->FPGA).

src/spi_base/spiifc.v

@@ -62,6 +62,114 @@ module spiifc(
   // Registers
   // 
   
+  reg  [ 7: 0] debug_reg;
+  
+  reg  [ 7: 0] rcByteReg;
+  reg          rcStarted;
+  reg  [ 2: 0] rcBitIndexReg;
+  reg  [11: 0] rcMemAddrReg;
+  
+  reg          ssPrev;
+  
+  reg          ssFastToggleReg;
+  reg          ssSlowToggle;
+  
+  reg          ssTurnOnReg;
+  reg          ssTurnOnHandled;
+  
+  //
+  // Wires
+  //
+  wire         rcByteValid; 
+  wire [ 7: 0] rcByte;
+  wire         rcStarting;
+  wire [ 2: 0] rcBitIndex;
+  
+  wire         ssTurnOn;
+  
+  wire         ssFastToggle;
+  
+  //
+  // Output assigns
+  //
+  assign debug_out = debug_reg;
+  
+  assign SPI_MISO = 0;
+  assign txMemAddr = 0;
+  
+  assign rcMemAddr = rcMemAddrReg;
+  assign rcMemData = rcByte;
+  assign rcMemWE = rcByteValid;
+  
+  assign ssFastToggle = 
+      (ssPrev == 1 && SPI_SS == 0 ? ~ssFastToggleReg : ssFastToggleReg);
+  
+  //
+  // Wire assigns
+  //
+  assign rcByteValid = rcStarted && rcBitIndex == 0;
+  assign rcByte = {rcByteReg[7:1], SPI_MOSI};
+  assign rcStarting = ssTurnOn;
+  assign rcBitIndex = (rcStarting ? 3'd7 : rcBitIndexReg);
+  
+  //assign ssTurnOn = ~ssTurnOnHandled & (ssTurnOnReg | (ssPrev & (~SPI_SS)));
+  assign ssTurnOn = ssSlowToggle ^ ssFastToggle;
+  
+  initial begin
+    ssSlowToggle <= 0;
+  end
+  
+  always @(posedge SysClk) begin
+    ssPrev <= SPI_SS;
+    
+    if (Reset) begin
+      ssTurnOnReg <= 0;
+      ssFastToggleReg <= 0;
+
+    end else begin
+      if (ssPrev & (~SPI_SS)) begin
+        ssTurnOnReg <= 1;
+        ssFastToggleReg <= ~ssFastToggleReg;
+        
+      end else if (ssTurnOnHandled) begin
+        ssTurnOnReg <= 0;
+      end
+    end
+    
+  end
+  
+  always @(posedge SPI_CLK) begin
+    ssSlowToggle <= ssFastToggle;
+  
+    if (Reset) begin
+      // Resetting
+      rcByteReg <= 8'h00;
+      rcStarted <= 0;
+      rcBitIndexReg <= 3'd7;
+      ssTurnOnHandled <= 0;
+      debug_reg <= 8'hFF;
+      
+    end else begin
+      // Not resetting
+      ssTurnOnHandled <= ssTurnOn;
+          
+      if (~SPI_SS) begin
+        rcByteReg[rcBitIndex] <= SPI_MOSI;
+        rcBitIndexReg <= rcBitIndex - 3'd1;
+        rcStarted <= 1;
+      end
+      
+      // We've just received a byte (well, currently receiving the last bit)
+      
+    if (rcByteValid) begin
+      // For now, just display on LEDs
+      debug_reg <= rcByte;
+    end
+      
+    end // Reset/Reset'
+  end
+  
+/*
 reg rcByte_valid;
 wire rcClockBridgeEmpty;
 wire readRcByte;
@@ -104,9 +212,11 @@ fifo_8bit_to_8bit txCmdClkBridge(
   .empty(txCmdClkBridgeEmpty) // output empty
 );
 
-  /*
-   * TRANSMIT: FPGA TO PC
-   */
+
+
+  //
+  // TRANSMIT: FPGA TO PC
+  //
   assign SPI_MISO = txMemData[bitIndex]; 
   
   reg [2:0]          bitIndex;
@@ -138,9 +248,9 @@ fifo_8bit_to_8bit txCmdClkBridge(
     end
   end
   
-  /*
-   * RECEIVE: PC TO FPGA 
-   */
+  //
+  // RECEIVE: PC TO FPGA 
+  //
    
   // Detect start of receive
   reg       ss_prev;
@@ -171,22 +281,22 @@ fifo_8bit_to_8bit txCmdClkBridge(
   assign rcMemWE   = rcMemWE_reg;
   
   always @(posedge SysClk) begin
-    /*
-    // About to receive
-    if (ss_negedge) begin
-      rcBitIndex <= 3'd7;
-      rcState <= `RC_STATE_CMD;
     
-      debug_reg[0] <= 1;
-    end
+//    // About to receive
+//    if (ss_negedge) begin
+//      rcBitIndex <= 3'd7;
+//      rcState <= `RC_STATE_CMD;
+//      
+//      debug_reg[0] <= 1;
+//    end
+//    
+//    // Receiving
+//    if (receiving) begin
+//      rcByte[rcBitIndex] <= SPI_MOSI;
+//      rcBitIndex <= rcBitIndex - 3'd1;
+//    end
+//    rcByte_valid <= (receiving && rcBitIndex == 3'd0 ? 1'b1 : 1'b0);
     
-    // Receiving
-    if (receiving) begin
-      rcByte[rcBitIndex] <= SPI_MOSI;
-      rcBitIndex <= rcBitIndex - 3'd1;
-    end
-    rcByte_valid <= (receiving && rcBitIndex == 3'd0 ? 1'b1 : 1'b0);
-    */
     
     // Handle the complete incoming byte
     if (rcByte_valid) begin
@@ -270,40 +380,40 @@ fifo_8bit_to_8bit txCmdClkBridge(
   //wire  [7:0]          rcByte;
   //assign rcByte = {rcByteReg[7:1], (SPI_SS == 1'b0 && bitIndex == 
   
-  /*
-  //
-  // Receive (GPU to SPI)
-  //
-  reg        SPI_SS_prev_cycle;
-  
-  // This is the register backing rcByteId. It is always one cycle
-  // behind the true value of rcByteId, which we have to do a little
-  // work to get instantaneously correct using wire logic.
-  reg   [31:0]  rcByteIdPrev;    
-  wire  [31:0]  rcByteId;
-  assign rcByteId = (SPI_SS_prev_cycle == 1 && SPI_SS == 0 ? 32'd0 : 32'd1 + rcByteIdPrev);
-
-  // 1 if we're receiving from GPC, 0 if not.
-  wire isRecv;
-  assign isRecv = ~SPI_SS;
 
-  // Bits to Byte aggregator
-  reg [2:0] rcBitId;
-  reg [7:0] rcByte;
-  
-  
-  reg [31:0]    rcSizeBytes;
-  
-  always @(posedge SPI_CLK) begin
-    if (1 == isRecv) begin
-      case (rcByteId)
-        0: rcSizeBytes[ 7: 0] <= 
-    end
-    
-    // Update registers for next cycle
-    SPI_SS_prev_cycle <= SPI_SS;
-    rcByteId <= rcByteIdPrev;
-  end
-  */
+//  //
+//  // Receive (GPU to SPI)
+//  //
+//  reg        SPI_SS_prev_cycle;
+//  
+//  // This is the register backing rcByteId. It is always one cycle
+//  // behind the true value of rcByteId, which we have to do a little
+//  // work to get instantaneously correct using wire logic.
+//  reg   [31:0]  rcByteIdPrev;    
+//  wire  [31:0]  rcByteId;
+//  assign rcByteId = (SPI_SS_prev_cycle == 1 && SPI_SS == 0 ? 32'd0 : 32'd1 + rcByteIdPrev);
+//
+//  // 1 if we're receiving from GPC, 0 if not.
+//  wire isRecv;
+//  assign isRecv = ~SPI_SS;
+//  
+//  // Bits to Byte aggregator
+//  reg [2:0] rcBitId;
+//  reg [7:0] rcByte;
+//  
+//  
+//  reg [31:0]    rcSizeBytes;
+//  
+//  always @(posedge SPI_CLK) begin
+//    if (1 == isRecv) begin
+//      case (rcByteId)
+//        0: rcSizeBytes[ 7: 0] <= 
+//    end
+//    
+//    // Update registers for next cycle
+//    SPI_SS_prev_cycle <= SPI_SS;
+//    rcByteId <= rcByteIdPrev;
+//  end
+*/
   
 endmodule

src/spi_base/spiifc_tb2.v

@@ -39,6 +39,7 @@ module spiifc_tb2;
 	wire [11:0] rcMemAddr;
 	wire [7:0] rcMemData;
 	wire rcMemWE;
+  wire [7:0] debug_out;
 
 	// Instantiate the Unit Under Test (UUT)
 	spiifc uut (
@@ -52,7 +53,8 @@ module spiifc_tb2;
 		.txMemData(txMemData), 
 		.rcMemAddr(rcMemAddr), 
 		.rcMemData(rcMemData), 
-		.rcMemWE(rcMemWE)
+		.rcMemWE(rcMemWE),
+    .debug_out(debug_out)
 	);
 
   task recvByte;
@@ -71,8 +73,16 @@ module spiifc_tb2;
     #20 SysClk = ~SysClk;
   end
 
+  reg SPI_CLK_en;
+  initial begin
+    #310
+    SPI_CLK_en = 1;
+  end
   always begin
-    #50 SPI_CLK = ~SPI_CLK;
+    #10
+    if (SPI_CLK_en) begin
+      #40 SPI_CLK = ~SPI_CLK;
+    end
   end
 
   integer fdRcBytes;
@@ -87,11 +97,18 @@ module spiifc_tb2;
     SysClk = 0;
     
 		SPI_CLK = 0;
+    SPI_CLK_en = 0;
 		SPI_MOSI = 0;
 		SPI_SS = 1;
 		txMemData = 0;
 
 		// Wait 100 ns for global reset to finish
+		#100;
+    Reset = 1;
+    
+    #100;
+    Reset = 0;
+    
     #100;
       
 		// Add stimulus here

src/spi_base/spiwrap.v

+`timescale 1ns / 1ps
+//////////////////////////////////////////////////////////////////////////////////
+// Company: 
+// Engineer: 
+// 
+// Create Date:    17:49:15 11/02/2011 
+// Design Name: 
+// Module Name:    spiwrap 
+// Project Name: 
+// Target Devices: 
+// Tool versions: 
+// Description: 
+//
+// Dependencies: 
+//
+// Revision: 
+// Revision 0.01 - File Created
+// Additional Comments: 
+//
+//////////////////////////////////////////////////////////////////////////////////
+module spiwrap(
+    input Reset,
+    input SysClk,
+    input spi_ss,
+    input spi_mosi,
+    input spi_clk,
+    output spi_miso,
+    output [7:0] leds
+    );
+
+wire [31:0] douta_dummy;
+
+wire [11:0] spi_addr;
+wire [ 7:0] spi_data;
+
+reg        initMem;
+reg [ 9:0] initMemAddr;
+reg [31:0] initMemData;
+
+always @(posedge SysClk) begin
+  if (Reset) begin
+    initMem <= 1'b1;
+    initMemAddr <= 10'h000;
+    //initMemData <= 32'hFF00_FF00;
+    initMemData <= 32'h5A6C_C6A5; /*32'h55CC_55CC*/;
+    
+  end else begin
+    if (initMem == 1'b1) begin
+      // Turn off init mem mode if formatted memory 
+      if (initMemAddr == 10'h3FF) begin
+        initMem <= 1'b0;
+      end
+    
+      // Increment init mem addr/data
+      initMemAddr <= initMemAddr + 10'h001;
+      //initMemData <= ~initMemData;
+    end
+  end
+end
+
+spimem spiMemTx (
+  .clka(SysClk), // input clka
+  .ena(1'b1), // input ena
+  .wea(initMem), // input [0 : 0] wea
+  .addra(initMemAddr), // input [9 : 0] addra
+  .dina(initMemData), // input [31 : 0] dina
+  .douta(douta_dummy), // output [31 : 0] douta
+  .clkb(spi_clk), // input clkb
+  .enb(1'b1), // input enb
+  .web(1'b0), // input [0 : 0] web
+  .addrb(spi_addr), // input [11 : 0] addrb
+  .dinb(8'h00), // input [7 : 0] dinb
+  .doutb(spi_data) // output [7 : 0] doutb
+);
+
+wire        spi_rcMem_we;
+wire [11:0] spi_rcMem_addr; 
+wire [ 7:0] spi_rcMem_data;
+wire [ 7:0] debug_out;
+wire [ 7:0] spi_rcMem_doutb_dummy;
+spimem spiMemRc (
+  .clka(SysClk),
+  .ena(1'b1),
+  .wea(1'b0),
+  .addra(10'h000),
+  .douta(debug_out),
+  .clkb(spi_clk),
+  .enb(1'b1),
+  .web(spi_rcMem_we),
+  .addrb(spi_rcMem_addr),
+  .dinb(spi_rcMem_data),
+  .doutb(spi_rcMem_doutb_dummy)
+);
+
+spiifc mySpiIfc (
+  .Reset(Reset),
+  .SysClk(SysClk),
+  .SPI_CLK(spi_clk),
+  .SPI_MISO(spi_miso),
+  .SPI_MOSI(spi_mosi),
+  .SPI_SS(spi_ss),
+  .txMemAddr(spi_addr),
+  .txMemData(spi_data),
+  .rcMemAddr(spi_rcMem_addr),
+  .rcMemData(spi_rcMem_data),
+  .rcMemWE(spi_rcMem_we),
+  .debug_out(leds)
+);
+
+
+
+//assign leds = debug_out;
+
+endmodule