Terminal can now scroll using the state machine.

diff --git a/VTerm.v b/VTerm.v
index 2793e4b8b368d92e381422b5404fc3642240199f..09b130093e4eb199536c2d4f12ca8c3c70d730a1 100644 (file)
--- a/VTerm.v
+++ b/VTerm.v
@@ -54,19 +54,22 @@ module VTerm(
        wire [2:0] csrow;
        wire [7:0] csdata;
        
-       wire [11:0] vraddr;
+       wire [10:0] vraddr;
        wire [7:0] vrdata;
        
-       wire [11:0] vwaddr;
+       wire [10:0] vwaddr;
        wire [7:0] vwdata;
-       wire vwr;
+       wire [7:0] serdata;
+       wire vwr, serwr;
+       wire [10:0] vscroll;
        
        wire odata;
        
        CharSet cs(cschar, csrow, csdata);
-       VideoRAM vram(clk25, vraddr, vrdata, vwaddr, vwdata, vwr);
+       VideoRAM vram(clk25, vraddr + vscroll, vrdata, vwaddr, vwdata, vwr);
        VDisplay dpy(clk25, x, y, vraddr, vrdata, cschar, csrow, csdata, odata);
-       SerRX rx(clk25, vwr, vwaddr, vwdata, serrx);
+       SerRX rx(clk25, serwr, serdata, serrx);
+       RXState rxsm(clk25, vwr, vwaddr, vwdata, vscroll, serwr, serdata);
        
        always @(posedge clk25) begin
                red <= border ? 0 : {3{odata}};
@@ -123,13 +126,13 @@ endmodule
 
 module VideoRAM(
        input pixclk,
-       input [11:0] raddr,
+       input [10:0] raddr,
        output reg [7:0] rdata,
-       input [11:0] waddr,
+       input [10:0] waddr,
        input [7:0] wdata,
        input wr);
        
-       reg [7:0] ram [80*25-1 : 0];
+       reg [7:0] ram [2047 : 0];
        
        always @(posedge pixclk)
                rdata <= ram[raddr];
@@ -143,7 +146,7 @@ module VDisplay(
        input pixclk,
        input [11:0] x,
        input [11:0] y,
-       output wire [11:0] raddr,
+       output wire [10:0] raddr,
        input [7:0] rchar,
        output wire [7:0] cschar,
        output wire [2:0] csrow,
@@ -174,7 +177,6 @@ endmodule
 module SerRX(
        input pixclk,
        output reg wr = 0,
-       output reg [11:0] waddr = 0,
        output reg [7:0] wchar = 0,
        input serialrx
 );
@@ -210,10 +212,8 @@ module SerRX(
                        endcase
                end
                
-               if (wr) begin
+               if (wr)
                        wr <= 0;
-                       waddr <= waddr + 1;
-               end
                
                if ((rx_state == 0) && (serialrx == 0) /*&& (rx_hasdata == 0)*/)                /* Wait half a period before advancing. */
                        rx_clkdiv <= `CLK_DIV / 2 + `CLK_DIV / 4;
@@ -224,3 +224,76 @@ module SerRX(
        end
 
 endmodule
+
+module RXState(
+       input clk25,
+       output reg vwr = 0,
+       output reg [10:0] vwaddr = 0,
+       output reg [7:0] vwdata = 0,
+       output reg [10:0] vscroll = 0,
+       input serwr,
+       input [7:0] serdata);
+
+       parameter STATE_IDLE = 4'b0000;
+       parameter STATE_NEWLINE = 4'b0001;
+       parameter STATE_CLEAR = 4'b0010;
+
+       reg [3:0] state = STATE_CLEAR;
+       
+       reg [6:0] x = 0;
+       reg [4:0] y = 0;
+       
+       reg [10:0] clearstart = 0;
+       reg [10:0] clearend = 11'b11111111111;
+       
+       always @(posedge clk25)
+               case (state)
+               STATE_IDLE:     if (serwr) begin
+                                       if (serdata == 8'h0A) begin
+                                               state <= STATE_NEWLINE;
+                                               vwr <= 0;
+                                       end else if (serdata == 8'h0D) begin
+                                               x <= 0;
+                                               vwr <= 0;
+                                       end else if (serdata == 8'h0C) begin
+                                               clearstart <= 0;
+                                               clearend <= 11'b11111111111;
+                                               x <= 0;
+                                               y <= 0;
+                                               vscroll <= 0;
+                                               state <= STATE_CLEAR;
+                                       end else begin
+                                               vwr <= 1;
+                                               vwaddr <= ({y,4'b0} + {y,6'b0} + {4'h0,x}) + vscroll;
+                                               vwdata <= serdata;
+                                               if (x == 79) begin
+                                                       x <= 0;
+                                                       state <= STATE_NEWLINE;
+                                               end else 
+                                                       x <= x + 1;
+                                       end
+                               end
+               STATE_NEWLINE:
+                       begin
+                               vwr <= 0;
+                               if (y == 24) begin
+                                       vscroll <= vscroll + 80;
+                                       clearstart <= (25 * 80) + vscroll;
+                                       clearend <= (26*80) + vscroll;
+                                       state <= STATE_CLEAR;
+                               end else begin
+                                       y <= y + 1;
+                                       state <= STATE_IDLE;
+                               end
+                       end
+               STATE_CLEAR:
+                       begin
+                               vwr <= 1;
+                               vwaddr <= clearstart;
+                               vwdata <= 8'h20;
+                               clearstart <= clearstart + 1;
+                               if (clearstart == clearend)
+                                       state <= STATE_IDLE;
+                       end
+               endcase
+endmodule