1 files changed, 123 insertions, 0 deletions
diff --git a/fpga_interchange/examples/tests/ram_nexus/ram_nexus.v b/fpga_interchange/examples/tests/ram_nexus/ram_nexus.v
new file mode 100644
index 00000000..e91a64bc
--- /dev/null
+++ b/fpga_interchange/examples/tests/ram_nexus/ram_nexus.v
@@ -0,0 +1,123 @@
+module ram0(
+    // Write port
+    input wrclk,
+    input [7:0] di,
+    input wren,
+    input [5:0] wraddr,
+    // Read port
+    input rdclk,
+    input rden,
+    input [5:0] rdaddr,
+    output reg [7:0] do);
+
+    (* syn_ramstyle = "block_ram" *) reg [7:0] ram[0:63];
+
+    initial begin
+        ram[0] = 8'b00000001;
+        ram[1] = 8'b10101010;
+        ram[2] = 8'b01010101;
+        ram[3] = 8'b11111111;
+        ram[4] = 8'b11110000;
+        ram[5] = 8'b00001111;
+        ram[6] = 8'b11001100;
+        ram[7] = 8'b00110011;
+        ram[8] = 8'b00000010;
+        ram[9] = 8'b00000100;
+    end
+
+    always @ (posedge wrclk) begin
+        if(wren == 1) begin
+            ram[wraddr] <= di;
+        end
+    end
+
+    always @ (posedge rdclk) begin
+        if(rden == 1) begin
+            do <= ram[rdaddr];
+        end
+    end
+
+endmodule
+
+module top (
+    input  wire clk,
+
+    input wire  pb0,
+    input wire  pb1,
+
+    input  wire [7:0] sw,
+    output wire [13:0] led
+);
+    wire bufclk;
+    DCC gbuf_i(.CLKI(clk), .CLKO(bufclk));
+
+
+    wire rden;
+    reg wren;
+    wire [5:0] rdaddr;
+    wire [5:0] wraddr;
+    wire [7:0] di;
+    wire [7:0] do;
+    ram0 ram(
+        .wrclk(bufclk),
+        .di(di),
+        .wren(wren),
+        .wraddr(wraddr),
+        .rdclk(bufclk),
+        .rden(rden),
+        .rdaddr(rdaddr),
+        .do(do)
+    );
+
+    reg [5:0] address_reg;
+    reg [7:0] data_reg;
+    reg [7:0] out_reg;
+
+    assign rdaddr = address_reg;
+    assign wraddr = address_reg;
+
+    // input_mode == 00 -> in[3:0] -> address_reg
+    // input_mode == 01 -> in[3:0] -> data_reg[3:0]
+    // input_mode == 10 -> in[3:0] -> data_reg[7:4]
+    // input_mode == 11 -> data_reg -> ram[address_reg]
+    wire [1:0] input_mode;
+
+    // WE == 0 -> address_reg and data_reg unchanged.
+    // WE == 1 -> address_reg or data_reg is updated because on input_mode.
+    wire we;
+
+    assign input_mode[0] = ~sw[6];
+    assign input_mode[1] = ~sw[7];
+
+    assign we = ~pb0;
+    assign led = ~{address_reg, out_reg};
+    assign di = data_reg;
+    assign rden = 1;
+
+    initial begin
+        wren = 1'b0;
+        address_reg = 10'b0;
+        data_reg = 16'b0;
+        out_reg = 16'b0;
+    end
+
+    always @ (posedge bufclk) begin
+        out_reg <= do;
+
+        if(we == 1) begin
+            if(input_mode == 0) begin
+                address_reg <= ~sw[5:0];
+                wren <= 0;
+            end else if(input_mode == 1) begin
+                data_reg[3:0] <= ~sw[3:0];
+                wren <= 0;
+            end else if(input_mode == 2) begin
+                data_reg[7:4] <= ~sw[3:0];
+                wren <= 0;
+            end else if(input_mode == 3) begin
+                wren <= 1;
+            end
+        end
+    end
+
+endmodule