Add the serial transmit module.

diff --git a/VTerm.ucf b/VTerm.ucf
index d8ba5a8d287ca03d875b5a85516b44fca9448b4b..036e41ab71dcb0e3d5f7a3b757af3906f7fe107e 100644 (file)
--- a/VTerm.ucf
+++ b/VTerm.ucf
@@ -1,4 +1,4 @@
-NET "xtal" LOC="B8" | CLOCK_DEDICATED_ROUTE = FALSE;
+NET "xtal" LOC="b8" | CLOCK_DEDICATED_ROUTE = FALSE;
 
 NET "vs" LOC="u3";
 NET "hs" LOC="t4";
@@ -11,4 +11,8 @@ NET "green<0>" LOC="n8";
 NET "blue<1>" LOC="u4";
 NET "blue<0>" LOC="u5";
 
-NET "serrx" LOC = "u6";
\ No newline at end of file
+NET "serrx" LOC="u6";
+NET "sertx" LOC="p9";
+
+NET "ps2c" LOC="r12" | CLOCK_DEDICATED_ROUTE = FALSE;
+NET "ps2d" LOC="p11";

diff --git a/VTerm.v b/VTerm.v
index 09b130093e4eb199536c2d4f12ca8c3c70d730a1..2cd9f3981f4b7fd2efea7a3eb2d04a8a9c13ccab 100644 (file)
--- a/VTerm.v
+++ b/VTerm.v
@@ -36,8 +36,9 @@ module VTerm(
        output reg [2:0] red,
        output reg [2:0] green,
        output reg [1:0] blue,
-       input serrx
-       );
+       input serrx,
+       output sertx,
+       input ps2c, ps2d);
        
        wire clk25;
 
@@ -69,6 +70,7 @@ module VTerm(
        VideoRAM vram(clk25, vraddr + vscroll, vrdata, vwaddr, vwdata, vwr);
        VDisplay dpy(clk25, x, y, vraddr, vrdata, cschar, csrow, csdata, odata);
        SerRX rx(clk25, serwr, serdata, serrx);
+       SerTX tx(clk25, 0, 0, sertx);
        RXState rxsm(clk25, vwr, vwaddr, vwdata, vscroll, serwr, serdata);
        
        always @(posedge clk25) begin
@@ -151,8 +153,7 @@ module VDisplay(
        output wire [7:0] cschar,
        output wire [2:0] csrow,
        input [7:0] csdata,
-       output reg data
-       );
+       output reg data);
 
        wire [7:0] col = x[11:3];
        wire [5:0] row = y[9:3];
@@ -178,8 +179,7 @@ module SerRX(
        input pixclk,
        output reg wr = 0,
        output reg [7:0] wchar = 0,
-       input serialrx
-);
+       input serialrx);
 
        reg [15:0] rx_clkdiv = 0;
        reg [3:0] rx_state = 4'b0000;
@@ -222,7 +222,50 @@ module SerRX(
                else
                        rx_clkdiv <= rx_clkdiv + 1;
        end
+endmodule
+
+module SerTX(
+       input pixclk,
+       input wr,
+       input [7:0] char,
+       output reg serial = 1);
+       
+       reg [7:0] tx_data = 0;
+       reg [15:0] tx_clkdiv = 0;
+       reg [3:0] tx_state = 4'b0000;
+       reg tx_busy = 0;
+       wire tx_newdata = wr && !tx_busy;
 
+       always @(posedge pixclk)
+       begin
+               if(tx_newdata) begin
+                       tx_data <= char;
+                       tx_state <= 4'b0000;
+                       tx_busy <= 1;
+               end else if (tx_clkdiv == 0) begin
+                       tx_state <= tx_state + 1;
+                       if (tx_busy)
+                               case (tx_state)
+                               4'b0000: serial <= 0;
+                               4'b0001: serial <= tx_data[0];
+                               4'b0010: serial <= tx_data[1];
+                               4'b0011: serial <= tx_data[2];
+                               4'b0100: serial <= tx_data[3];
+                               4'b0101: serial <= tx_data[4];
+                               4'b0110: serial <= tx_data[5];
+                               4'b0111: serial <= tx_data[6];
+                               4'b1000: serial <= tx_data[7];
+                               4'b1001: serial <= 1;
+                               4'b1010: tx_busy <= 0;
+                               default: $stop;
+                               endcase
+               end
+               
+               if(tx_newdata || (tx_clkdiv == `CLK_DIV))
+                       tx_clkdiv <= 0;
+               else
+                       tx_clkdiv <= tx_clkdiv + 1;
+       end
 endmodule
 
 module RXState(