Add SRAM memory model

1 files changed, 94 insertions, 0 deletions

diff --git a/atk16_fpga/sram_tb.v b/atk16_fpga/sram_tb.v
new file mode 100644
index 0000000..c734395
--- /dev/null
+++ b/atk16_fpga/sram_tb.v
@@ -0,0 +1,94 @@
+`default_nettype none
+`define DUMPSTR(x) `"x.vcd`"
+`timescale 1 ns / 100 ps
+
+module sram_tb();
+
+    reg clk, cs_n, wr_n, rd_n;
+    reg [17:0] addr;
+    reg [15:0] data_in;
+    wire [15:0] data_out;
+
+    sram dut(
+        .cs_n(cs_n),
+        .wr_n(wr_n),
+        .rd_n(rd_n),
+        .addr(addr),
+        .data_in(data_in),
+        .data_out(data_out)
+    );
+
+    wire [15:0] debug_mem100;
+    assign debug_mem100 = dut.mem[100];
+
+    reg failed;
+    initial begin
+        failed = 0;
+        $dumpfile(`DUMPSTR(`VCD_OUTPUT));
+        $dumpvars(0, sram_tb);
+
+        cs_n = 1;
+        wr_n = 1;
+        rd_n = 1;
+        addr = 18'd0;
+        data_in = 16'h0;
+        #10
+
+        // test write
+        cs_n = 0;
+        wr_n = 0;
+        addr = 18'd100;
+        data_in = 16'h1234;
+
+        #5
+        if (debug_mem100 === 16'hx) begin
+            $display("\033[0;32m[PASS]\033[0m Write: data is invalid at time: %0d ns", $time);
+        end else begin
+            $display("\033[0;31m[FAIL]\033[0m Write: data is valid too early, got %04h at time %0d ns", debug_mem100, $time);
+            failed = 1;
+        end
+
+        #5
+        if (debug_mem100 == 16'h1234) begin
+            $display("\033[0;32m[PASS]\033[0m Write: data is written as expected");
+        end else begin
+            $display("\033[0;31m[FAIL]\033[0m Write: data is %04h (expected 1234)", debug_mem100);
+            failed = 1;
+        end
+
+        cs_n = 1;
+        wr_n = 1;
+        #100;
+
+        // test read
+        cs_n = 0;
+        rd_n = 0;
+        addr = 18'd100;
+
+        #5
+        if (data_out === 16'hx) begin
+            $display("\033[0;32m[PASS]\033[0m Read: data is invalid at time: %0d ns", $time);
+        end else begin
+            $display("\033[0;31m[FAIL]\033[0m Read: data is valid too early, got %04h at time %0d ns", data_out, $time);
+            failed = 1;
+        end
+
+        #5
+        if (data_out == 16'h1234) begin
+            $display("\033[0;32m[PASS]\033[0m Read: data is available as expected");
+        end else begin
+            $display("\033[0;31m[FAIL]\033[0m Read: data is %04h (expected 1234)", data_out);
+            failed = 1;
+        end
+
+        #100
+
+        if (!failed) begin
+            $display("\033[0;32m[PASS]\033[0m All tests passed");
+        end else begin
+            $display("\033[0;31m[FAIL]\033[0m Some tests failed");
+        end
+        $finish;
+    end
+
+endmodule