Subversion Repositories rtf68ksys

// ============================================================================

//      (C) 2006-2011  Robert Finch

//      robfinch@<remove>opencores.org

//

//      rtfTextController.v

//              text controller

//

// This source file is free software: you can redistribute it and/or modify 

// it under the terms of the GNU Lesser General Public License as published 

// by the Free Software Foundation, either version 3 of the License, or     

// (at your option) any later version.                                      

//                                                                          

// This source file is distributed in the hope that it will be useful,      

// but WITHOUT ANY WARRANTY; without even the implied warranty of           

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            

// GNU General Public License for more details.                             

//                                                                          

// You should have received a copy of the GNU General Public License        

// along with this program.  If not, see <http://www.gnu.org/licenses/>.    

//                                                                          

//

//      Text Controller

//

//      FEATURES

//

//      This core requires an external timing generator to provide horizontal

//      and vertical sync signals, but otherwise can be used as a display

//  controller on it's own. However, this core may also be embedded within

//  another core such as a VGA controller.

//

//      Window positions are referenced to the rising edge of the vertical and

//      horizontal sync pulses.

//

//      The core includes an embedded dual port RAM to hold the screen

//      characters.

//

//

//--------------------------------------------------------------------

// Registers

//

//      00 -         nnnnnnnn  number of columns (horizontal displayed number of characters)

//      01 -         nnnnnnnn  number of rows    (vertical displayed number of characters)

//      02 -       n nnnnnnnn  window left       (horizontal sync position - reference for left edge of displayed)

//      03 -       n nnnnnnnn  window top        (vertical sync position - reference for the top edge of displayed)

//      04 -         ---nnnnn  maximum scan line (char ROM max value is 7)

//              05 -         hhhhwwww  pixel size, hhhh=height,wwww=width

//      07 -         ---nnnnn  color code for transparent background

//      08 -         -BPnnnnn  cursor start / blink control

//                             BP: 00=no blink

//                             BP: 01=no display

//                             BP: 10=1/16 field rate blink

//                             BP: 11=1/32 field rate blink

//      09 -        ----nnnnn  cursor end

//      10 - aaaaaaaa aaaaaaaaa  start address (index into display memory)

//      11 - aaaaaaaa aaaaaaaaa  cursor position

//      12 - aaaaaaaa aaaaaaaaa  light pen position

//--------------------------------------------------------------------

//

// ============================================================================

module rtfTextController(

        rst_i, clk_i,

        cyc_i, stb_i, ack_o, we_i, sel_i, adr_i, dat_i, dat_o,

        lp, curpos,

        vclk, eol, eof, blank, border, rgbIn, rgbOut

);

parameter COLS = 12'd52;

parameter ROWS = 12'd31;

// Syscon

input  rst_i;                   // reset

input  clk_i;                   // clock

// Slave signals

input  cyc_i;                   // cycle valid

input  stb_i;                   // data strobe

output ack_o;                   // transfer acknowledge

input  we_i;                    // write

input  [ 1:0] sel_i;     // byte select

input  [31:0] adr_i;     // address

input  [15:0] dat_i;     // data input

output [15:0] dat_o;     // data output

reg    [15:0] dat_o;

//

input lp;                               // light pen

input [15:0] curpos;     // cursor position

// Video signals

input vclk;                             // video dot clock

input eol;                              // end of scan line

input eof;                              // end of frame

input blank;                    // blanking signal

input border;                   // border area

input [24:0] rgbIn;              // input pixel stream

output reg [24:0] rgbOut;        // output pixel stream

wire [23:0] bkColor24;   // background color

wire [23:0] fgColor24;   // foreground color

wire [23:0] tcColor24;   // transparent color

wire pix;                               // pixel value from character generator 1=on,0=off

reg [15:0] rego;

reg [11:0] windowTop;

reg [11:0] windowLeft;

reg [11:0] numCols;

reg [11:0] numRows;

reg [ 1:0] mode;

reg [ 4:0] maxScanline;

reg [ 4:0] maxScanpix;

reg [ 4:0] cursorStart, cursorEnd;

reg [15:0] cursorPos;

reg [15:0] startAddress;

reg [ 2:0] rBlink;

reg [ 3:0] bdrColorReg;

reg [ 3:0] pixelWidth;   // horizontal pixel width in clock cycles

reg [ 3:0] pixelHeight;  // vertical pixel height in scan lines

wire [11:0] hctr;                // horizontal reference counter (counts clocks since hSync)

wire [11:0] scanline;    // scan line

wire [11:0] row;         // vertical reference counter (counts rows since vSync)

wire [11:0] col;         // horizontal column

reg  [ 4:0] rowscan;     // scan line within row

wire nxt_row;                   // when to increment the row counter

wire nxt_col;                   // when to increment the column counter

wire [ 5:0] bcnt;                // blink timing counter

wire blink;

reg  iblank;

wire nhp;                               // next horizontal pixel

wire ld_shft = nxt_col & nhp;

// display and timing signals

reg [15:0] txtAddr;              // index into memory

reg [15:0] penAddr;

wire [8:0] txtOut;               // character code

wire [7:0] charOut;              // character ROM output

wire [3:0] txtBkCode;    // background color code

wire [4:0] txtFgCode;    // foreground color code

reg  [4:0] txtTcCode;    // transparent color code

reg  bgt;

wire [8:0] tdat_o;

wire [8:0] cdat_o;

wire [7:0] chdat_o;

wire [2:0] scanindex = scanline[2:0];

//--------------------------------------------------------------------

// Address Decoding

// I/O range FFDx

//--------------------------------------------------------------------

wire cs_text = cyc_i && stb_i && (adr_i[31:16]==16'hFFD0);

wire cs_color= cyc_i && stb_i && (adr_i[31:16]==16'hFFD1);

wire cs_rom  = cyc_i && stb_i && (adr_i[31:16]==16'hFFD2);

wire cs_reg  = cyc_i && stb_i && (adr_i[31: 8]==24'hFFDA_00);

always @(cs_text or cs_color or cs_rom or cs_reg or tdat_o or cdat_o or chdat_o or rego)

        if (cs_text) dat_o <= tdat_o;

        else if (cs_color) dat_o <= cdat_o;

        else if (cs_rom) dat_o <= chdat_o;

        else if (cs_reg) dat_o <= rego;

        else dat_o <= 16'h0000;

//--------------------------------------------------------------------

// Video Memory

//--------------------------------------------------------------------

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

// Address Calculation:

//  - Simple: the row times the number of  cols plus the col plue the

//    base screen address

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

wire [17:0] rowcol = row * numCols;

always @(posedge vclk)

        txtAddr <= startAddress + rowcol + col;

// text screen RAM

syncRam4kx9_1rw1r textRam0

(

        .wclk(clk_i),

        .wadr(adr_i[13:1]),

        .i(dat_i),

        .wo(tdat_o),

        .wce(cs_text),

        .we(we_i),

        .wrst(1'b0),

        .rclk(vclk),

        .radr(txtAddr[12:0]),

        .o(txtOut),

        .rce(ld_shft),

        .rrst(1'b0)

);

// screen attribute RAM

syncRam4kx9_1rw1r colorRam0

(

        .wclk(clk_i),

        .wadr(adr_i[13:1]),

        .i(dat_i),

        .wo(cdat_o),

        .wce(cs_color),

        .we(we_i),

        .wrst(1'b0),

        .rclk(vclk),

        .radr(txtAddr[12:0]),

        .o({txtBkCode,txtFgCode}),

        .rce(ld_shft),

        .rrst(1'b0)

);

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

// Character bitmap ROM

// - room for 512 characters

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

syncRam4kx9_1rw1r charRam0

(

        .wclk(clk_i),

        .wadr(adr_i[11:0]),

        .i(dat_i),

        .wo(chdat_o),

        .wce(cs_rom),

        .we(we_i),

        .wrst(1'b0),

        .rclk(vclk),

        .radr({txtOut,rowscan[2:0]}),

        .o(charOut),

        .rce(ld_shft),

        .rrst(1'b0)

);

// pipeline delay - sync color with character bitmap output

reg [3:0] txtBkCode1;

reg [4:0] txtFgCode1;

always @(posedge vclk)

        if (nhp & ld_shft) txtBkCode1 <= txtBkCode;

always @(posedge vclk)

        if (nhp & ld_shft) txtFgCode1 <= txtFgCode;

//--------------------------------------------------------------------

// bus interfacing

// - there is a one cycle latency for reads, an ack is generated

//   after the synchronous RAM read

// - writes can be acknowledged right away.

//--------------------------------------------------------------------

reg ramRdy;

always @(posedge clk_i)

        ramRdy = cs_text|cs_rom|cs_color|cs_reg;

assign ack_o = (cyc_i & stb_i) ? (we_i ? (cs_text|cs_color|cs_rom|cs_reg) : ramRdy) : 1'b0;

//--------------------------------------------------------------------

// Registers

//

//      00 -         nnnnnnnn  number of columns (horizontal displayed number of characters)

//      01 -         nnnnnnnn  number of rows    (vertical displayed number of characters)

//      02 -       n nnnnnnnn  window left       (horizontal sync position - reference for left edge of displayed)

//      03 -       n nnnnnnnn  window top        (vertical sync position - reference for the top edge of displayed)

//      04 -         ---nnnnn  maximum scan line (char ROM max value is 7)

//              05 -         hhhhwwww  pixel size, hhhh=height,wwww=width

//      08 -         -BPnnnnn  cursor start / blink control

//                             BP: 00=no blink

//                             BP: 01=no display

//                             BP: 10=1/16 field rate blink

//                             BP: 11=1/32 field rate blink

//      09 -        ----nnnnn  cursor end

//      10 - aaaaaaaa aaaaaaaaa  start address (index into display memory)

//      11 - aaaaaaaa aaaaaaaaa  cursor position

//      12 - aaaaaaaa aaaaaaaaa  light pen position

//--------------------------------------------------------------------

//--------------------------------------------------------------------

// Light Pen

//--------------------------------------------------------------------

wire lpe;

edge_det u1 (.rst(rst_i), .clk(clk_i), .ce(1'b1), .i(lp), .pe(lpe), .ne(), .ee() );

always @(posedge clk_i)

        if (rst_i)

                penAddr <= 32'h0000_0000;

        else begin

                if (lpe)

                        penAddr <= txtAddr;

        end

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

// Register read port

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

always @(cs_reg or cursorPos or penAddr or adr_i)

        if (cs_reg) begin

                case(adr_i[4:1])

                4'd0:           rego <= numCols;

                4'd1:           rego <= numRows;

                4'd11:          rego <= cursorPos;

                4'd12:          rego <= penAddr;

                default:        rego <= 16'h0000;

                endcase

        end

        else

                rego <= 16'h0000;

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

// Register write port

//- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

reg interlace;

always @(posedge clk_i)

        if (rst_i) begin

// 104x63

/*

                windowTop    <= 12'd26;

                windowLeft   <= 12'd260;

                pixelWidth   <= 4'd0;

                pixelHeight  <= 4'd1;           // 525 pixels (408 with border)

*/

// 52x31

                windowTop    <= 12'd14;

                windowLeft   <= 12'd117;

                pixelWidth   <= 4'd1;

                pixelHeight  <= 4'd3;           // 262 pixels (248 with border)

                numCols      <= COLS;

                numRows      <= ROWS;

                maxScanline  <= 5'd7;

                maxScanpix   <= 5'd7;

                rBlink       <= 3'b111;         // 01 = non display

                startAddress <= 16'h0000;

                cursorStart  <= 5'd00;

                cursorEnd    <= 5'd31;

                cursorPos    <= 16'h0003;

                txtTcCode    <= 5'd31;

        end

        else begin

                if (cs_reg & we_i) begin        // register write ?

                        case(adr_i[4:1])

                        4'd00:  numCols    <= dat_i;            // horizontal displayed

                        4'd01:  numRows    <= dat_i;

                        4'd02:  windowLeft <= dat_i[11:0];

                        4'd03:  windowTop  <= dat_i[11:0];               // vertical sync position

                        4'd04:  maxScanline <= dat_i[4:0];

                        4'd05:  begin

                                        pixelHeight <= dat_i[7:4];

                                        pixelWidth  <= dat_i[3:0];       // horizontal pixel width

                                        end

                        4'd07:  txtTcCode   <= dat_i[4:0];

                        4'd08:  begin

                                        cursorStart <= dat_i[4:0];       // scan line sursor starts on

                                        rBlink      <= dat_i[7:5];

                                        end

                        4'd09:  cursorEnd   <= dat_i[4:0];       // scan line cursor ends on

                        4'd10:  startAddress <= dat_i;

                        4'd11:  cursorPos <= dat_i;

                        endcase

                end

        end

//--------------------------------------------------------------------

//--------------------------------------------------------------------

// "Box" cursor bitmap

reg [7:0] curout;

always @(scanindex)

        case(scanindex)

        3'd0:   curout = 8'b11111111;

        3'd1:   curout = 8'b10000001;

        3'd2:   curout = 8'b10000001;

        3'd3:   curout = 8'b10000001;

        3'd4:   curout = 8'b10000001;

        3'd5:   curout = 8'b10000001;

        3'd6:   curout = 8'b10011001;

        3'd7:   curout = 8'b11111111;

        endcase

//-------------------------------------------------------------

// Video Stuff

//-------------------------------------------------------------

// Horizontal counter:

//

HVCounter uhv1

(

        .rst(rst_i),

        .vclk(vclk),

        .pixcce(1'b1),

        .sync(eol),

        .cnt_offs(windowLeft),

        .pixsz(pixelWidth),

        .maxpix(maxScanpix),

        .nxt_pix(nhp),

        .pos(col),

        .nxt_pos(nxt_col),

        .ctr(hctr)

);

// Vertical counter:

//

HVCounter uhv2

(

        .rst(rst_i),

        .vclk(vclk),

        .pixcce(eol),

        .sync(eof),

        .cnt_offs(windowTop),

        .pixsz(pixelHeight),

        .maxpix(maxScanline),

        .nxt_pix(nvp),

        .pos(row),

        .nxt_pos(nxt_row),

        .ctr(scanline)

);

always @(posedge vclk)

        rowscan <= scanline - row * (maxScanline+1);

// Blink counter

//

VT163 #(6) ub1

(

        .clk(vclk),

        .clr_n(!rst_i),

        .ent(eol & eof),

        .enp(1'b1),

        .ld_n(1'b1),

        .d(6'd0),

        .q(bcnt)

);

wire blink_en = (cursorPos+2==txtAddr) && (scanline[4:0] >= cursorStart) && (scanline[4:0] <= cursorEnd);

VT151 ub2

(

        .e_n(!blink_en),

        .s(rBlink),

        .i0(1'b1), .i1(1'b0), .i2(bcnt[4]), .i3(bcnt[5]),

        .i4(1'b1), .i5(1'b0), .i6(bcnt[4]), .i7(bcnt[5]),

        .z(blink),

        .z_n()

);

// These tables map a five bit color code to an eight bit color value.

rtfColorROM ucm1 (.clk(vclk), .ce(nhp & ld_shft), .code(txtBkCode1),  .color(bkColor24) );

rtfColorROM ucm2 (.clk(vclk), .ce(nhp & ld_shft), .code(txtFgCode1),  .color(fgColor24) );

always @(posedge vclk)

        if (nhp & ld_shft)

                bgt <= {1'b0,txtBkCode1}==txtTcCode;

// Convert character bitmap to pixels

// For convenience, the character bitmap data in the ROM is in the

// opposite bit order to what's needed for the display. The following

// just alters the order without adding any hardware.

//

wire [7:0] charRev = {

        charOut[0],

        charOut[1],

        charOut[2],

        charOut[3],

        charOut[4],

        charOut[5],

        charOut[6],

        charOut[7]

};

wire [7:0] charout1 = blink ? (charRev ^ curout) : charRev;

// Convert parallel to serial

ParallelToSerial ups1

(

        .rst(rst_i),

        .clk(vclk),

        .ce(nhp),

        .ld(ld_shft),

        .qin(1'b0),

        .d(charout1),

        .qh(pix)

);

// Pipelining Effect:

// - character output is delayed by 3 character times relative to the video counters.

// - this means we must adapt the blanking signal by shifting the blanking window

//   three character times.

wire bpix = hctr[1] ^ scanline[4];// ^ blink;

always @(posedge vclk)

        if (nhp)

                iblank <= (row >= numRows) || (col >= numCols + 3) || (col < 3);

// Choose between input RGB and controller generated RGB

// Select between foreground and background colours.

always @(posedge vclk)

        if (nhp) begin

                casex({blank,iblank,border,bpix,pix})

                5'b1xxxx:       rgbOut <= 25'h0000000;

                5'b01xxx:       rgbOut <= rgbIn;

                5'b0010x:       rgbOut <= 24'hBF2020;

                5'b0011x:       rgbOut <= 24'hDFDFDF;

                5'b000x0:       rgbOut <= bgt ? rgbIn : bkColor24;

                5'b000x1:       rgbOut <= fgColor24;

                default:        rgbOut <= rgbIn;

                endcase

        end

endmodule