X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/a02672555adf08bfd6755cf70599895dd2155a24..e7fb589a21ee26ad897e03cbd0d7a647d9cd97e5:/Uart.v diff --git a/Uart.v b/Uart.v index 1cc839a..1f0ae7d 100644 --- a/Uart.v +++ b/Uart.v @@ -1,5 +1,5 @@ -`define IN_CLK 8400000 -`define OUT_CLK 9600 +`define IN_CLK 8388608 +`define OUT_CLK 57600 `define CLK_DIV `IN_CLK / `OUT_CLK `define MMAP_ADDR 16'hFF50 @@ -8,30 +8,35 @@ 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 -`define FUQING 4'b1010 /* deal with diqing */ - if(new) begin - data_stor <= ~data; + if(newdata) begin + 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]; @@ -40,14 +45,14 @@ 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 end /* deal with clkdiv */ - if((new && !have_data) || clkdiv == `CLK_DIV) + if((newdata && !have_data) || clkdiv == `CLK_DIV) clkdiv <= 0; else clkdiv <= clkdiv + 1;