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vga framebuffer: use 640x480@60Hz video timings

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- we still can only display 400 lines, so 80 blank lines
  are added at the bottom
- we get square pixels this way and are hopefully more
  compatible with monitors and other devices like
  scan converters and capture cards
This commit is contained in:
slederer 2025-06-22 00:33:02 +02:00
parent e08d610aef
commit ecff04a7a0
2 changed files with 39 additions and 18 deletions
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27
tridoracpu/tridoracpu.srcs/vgafb.v
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@ -6,8 +6,11 @@
// Learn more at https://projectf.io
//128K video memory is not enough for 640x480x4
`define RES_640_400
//`define RES_640_400
//`define RES_1024_768
// RES_640_480 mode displays 400 lines with 640x480/60 video timings,
// adding blank lines at the bottom
`define RES_640_480
module display_timings #(
H_RES=640, // horizontal resolution (pixels)
@ -126,6 +129,8 @@ module vgafb #(VMEM_ADDR_WIDTH = 15, VMEM_DATA_WIDTH = 32) (
localparam COLOR_WIDTH = 12;
localparam PALETTE_WIDTH = 4;
localparam signed PIC_LINES = 400; // visible picture lines
// Display Clocks
wire pix_clk = CLK; // pixel clock
wire clk_lock = 1; // clock locked?
@ -202,6 +207,18 @@ module vgafb #(VMEM_ADDR_WIDTH = 15, VMEM_DATA_WIDTH = 32) (
.V_BP(35),
.H_POL(0),
.V_POL(1)
`endif
`ifdef RES_640_480
.H_RES(640), // 640 800 1280 1920
.V_RES(480), // 480 600 720 1080
.H_FP(16), // 16 40 110 88
.H_SYNC(96), // 96 128 40 44
.H_BP(48), // 48 88 220 148
.V_FP(10), // 10 1 5 4
.V_SYNC(2), // 2 4 5 5
.V_BP(33), // 33 23 20 36
.H_POL(0), // 0 1 1 1
.V_POL(0) // 0 1 1 1
`endif
)
display_timings_inst (
@ -217,6 +234,8 @@ module vgafb #(VMEM_ADDR_WIDTH = 15, VMEM_DATA_WIDTH = 32) (
.o_sy(sy)
);
wire pic_enable = (sy >= 0) && (sy < PIC_LINES); // when to display pixels from VRAM
wire [7:0] red;
wire [7:0] green;
wire [7:0] blue;
@ -288,7 +307,7 @@ module vgafb #(VMEM_ADDR_WIDTH = 15, VMEM_DATA_WIDTH = 32) (
// 12 bit RGB palette
assign VGA_HS = h_sync;
assign VGA_VS = v_sync;
assign VGA_R = de ? color_data[11:8] : 4'b0;
assign VGA_G = de ? color_data[7:4] : 4'b0;
assign VGA_B = de ? color_data[3:0] : 4'b0;
assign VGA_R = (pic_enable && de) ? color_data[11:8] : 4'b0;
assign VGA_G = (pic_enable && de) ? color_data[7:4] : 4'b0;
assign VGA_B = (pic_enable && de) ? color_data[3:0] : 4'b0;
endmodule