Completed first RTL for the SPI slave. Simplified the design to simply be two shift registers and a somple FSM that detects clock flanks and SS.

1 files changed, 28 insertions, 4 deletions

diff --git a/src/rtl/fpga_mkm.v b/src/rtl/fpga_mkm.v
index eb6172d..e0dc14a 100644
--- a/src/rtl/fpga_mkm.v
+++ b/src/rtl/fpga_mkm.v
@@ -40,6 +40,8 @@
 module fpga_mkm(
                 input wire clk,
 
+                // SPI slave interface ports.
+                input wire ss,
                 input wire sclk,
                 input wire mosi,
                 output wire miso,
@@ -66,9 +68,14 @@ module fpga_mkm(
   localparam CTRL_DONE  = 3;
 
 
+  localparam MEM_WORDS = 16;
+
+
   //----------------------------------------------------------------
   // Registers including update variables and write enable.
   //----------------------------------------------------------------
+  reg [31 : 0] key_mem [0 : (MEM_WORDS - 1)];
+
   reg [21 : 0] alarm_counter_reg = 22'h0;
 
   reg alarm_reg = 1'h0;
@@ -95,8 +102,23 @@ module fpga_mkm(
   assign rled4 = alarm_counter_reg[21];
   assign gled5 = key_loaded_reg;
 
-  assign miso  = miso_reg;
-  assign alarm = alarm_reg;
+
+
+  //----------------------------------------------------------------
+  // Module instantiations.
+  //----------------------------------------------------------------
+  fpga_mkm_spi_slave spi_slave(
+                               .clk(clk),
+                               .ss(ss),
+                               .sclk(sclk),
+                               .mosi(mosi),
+                               .miso(miso),
+                               .spi_active(),
+                               .rx_byte_available(),
+                               .rx_byte(),
+                               .tx_byte_load(),
+                               .tx_byte()
+                              );
 
 
   //----------------------------------------------------------------
@@ -104,10 +126,12 @@ module fpga_mkm(
   //----------------------------------------------------------------
   always @ (posedge clk or negedge tamper)
     begin : reg_update
+      integer i;
+
       if (!tamper)
         begin
-          // Zeroise the key material!
-
+          for (i = 0 ; i < MEM_WORDS ; i = i + 1)
+            key_mem[i] <= 32'h0;
         end
       else
         begin