1 files changed, 67 insertions, 0 deletions
diff --git a/atk16_fpga/mem_fsm.v b/atk16_fpga/mem_fsm.v
new file mode 100644
index 0000000..d5419c5
--- /dev/null
+++ b/atk16_fpga/mem_fsm.v
@@ -0,0 +1,67 @@
+`default_nettype none
+
+`define ST_IDLE   3'd0
+`define ST_READ1  3'd1
+`define ST_READ2  3'd2
+`define ST_WRITE1 3'd4
+`define ST_WRITE2 3'd5
+`define ST_END    3'd7
+
+module mem_fsm(
+    input clk,
+    input [15:0] addr,
+    input [15:0] data_in,
+    input read_en,
+    input write_en,
+
+    output wire [15:0] data_out,
+    output reg done
+);
+    reg wr, rd;
+    reg [15:0] bram_addr;
+    reg [2:0] state = 0;
+    bram bram_inst(
+        .clk(clk),
+        .addr(bram_addr),
+        .cs_n(0),
+        .wr_n(~wr),
+        .rd_n(~rd),
+        .bram_data_in(data_in),
+        .bram_data_out(data_out)
+    );
+
+    always @(posedge clk) begin
+        case (state)
+            `ST_IDLE: begin
+                done <= 0;
+                if (~done && read_en) begin
+                    state <= `ST_READ1;
+                    bram_addr <= addr;
+                    rd <= 1;
+                    wr <= 0;
+                end
+                else if (~done && write_en) begin
+                    state <= `ST_WRITE1;
+                    bram_addr <= addr;
+                    rd <= 0;
+                    wr <= 1;
+                end
+            end
+            `ST_READ1: begin
+                state <= `ST_READ2;
+            end
+            `ST_READ2: begin
+                state <= `ST_IDLE;
+                done <= 1;
+            end
+            `ST_WRITE1: begin
+                state <= `ST_WRITE2;
+            end
+            `ST_WRITE2: begin
+                state <= `ST_IDLE;
+                done <= 1;
+            end
+        endcase
+    end
+
+endmodule