Hello, Z80!

[fpgaboy.git] / Uart.v

diff --git a/Uart.v b/Uart.v
index 1cc839a77ff584b615da50fc01676646897b4b14..a036c64e5ad7858422f27515730da6d13c15c9d0 100644 (file)
--- a/Uart.v
+++ b/Uart.v
@@ -1,4 +1,4 @@
-`define IN_CLK 8400000
+`define IN_CLK 8388608
 `define OUT_CLK 9600
 `define CLK_DIV `IN_CLK / `OUT_CLK
 `define MMAP_ADDR 16'hFF50
@@ -8,8 +8,13 @@ module UART(
        input wr,
        input rd,
        input [15:0] addr,
-       input [7:0] data,
+       inout [7:0] data,
        output reg serial);
+       
+       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;
@@ -17,21 +22,22 @@ module UART(
        reg data_end = 0;
        reg [3:0] diqing = 4'b0000;
        
-       wire new = (wr) && (!have_data) && (addr == `MMAP_ADDR);
+       wire new = (wr) && (!have_data) && decode;
+       
+       assign odata = have_data ? 8'b1 : 8'b0;
 
        always @ (negedge clk)
        begin
-`define FUQING 4'b1010
                /* deal with diqing */
                if(new) begin
-                       data_stor <= ~data;
+                       data_stor <= data;
                        have_data <= 1;
                        diqing <= 4'b0000;
                end else if (clkdiv == 0) begin
                        diqing <= diqing + 1;
                        if (have_data)
                                case (diqing)
-                               4'b0000: serial <= 1;
+                               4'b0000: serial <= 0;
                                4'b0001: serial <= data_stor[0];
                                4'b0010: serial <= data_stor[1];
                                4'b0011: serial <= data_stor[2];
@@ -40,7 +46,7 @@ module UART(
                                4'b0110: serial <= data_stor[5];
                                4'b0111: serial <= data_stor[6];
                                4'b1000: serial <= data_stor[7];
-                               4'b1001: serial <= 0;
+                               4'b1001: serial <= 1;
                                4'b1010: have_data <= 0;
                                default: $stop;
                        endcase