Add some verilator and isim compatibility
[fpgaboy.git] / Uart.v
diff --git a/Uart.v b/Uart.v
index f8ee27b..1f0ae7d 100644 (file)
--- a/Uart.v
+++ b/Uart.v
@@ -1,5 +1,5 @@
 `define IN_CLK 8388608
-`define OUT_CLK 9600
+`define OUT_CLK 57600
 `define CLK_DIV `IN_CLK / `OUT_CLK
 `define MMAP_ADDR 16'hFF50
 
@@ -8,21 +8,27 @@ module UART(
        input wr,
        input rd,
        input [15:0] addr,
-       input [7:0] data,
-       output reg serial);
+       inout [7:0] data,
+       output reg serial = 1);
+       
+       wire decode = (addr == `MMAP_ADDR);
+       
+       wire [7:0] odata;
+       assign data = (rd && decode) ? odata : 8'bzzzzzzzz;
 
        reg [7:0] data_stor = 0;
        reg [15:0] clkdiv = 0;
        reg have_data = 0;
-       reg data_end = 0;
        reg [3:0] diqing = 4'b0000;
        
-       wire new = (wr) && (!have_data) && (addr == `MMAP_ADDR);
+       wire newdata = (wr) && (!have_data) && decode;
+       
+       assign odata = have_data ? 8'b1 : 8'b0;
 
        always @ (negedge clk)
        begin
                /* deal with diqing */
-               if(new) begin
+               if(newdata) begin
                        data_stor <= data;
                        have_data <= 1;
                        diqing <= 4'b0000;
@@ -46,7 +52,7 @@ module UART(
                end
 
                /* deal with clkdiv */
-               if((new && !have_data) || clkdiv == `CLK_DIV)
+               if((newdata && !have_data) || clkdiv == `CLK_DIV)
                        clkdiv <= 0;
                else
                        clkdiv <= clkdiv + 1;
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