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Cleaning VGA mode generation (now using same timings/code as HDMI

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generation in FemtoRV/FemtoSOC)
This commit is contained in:
Bruno Levy
2021-03-30 18:25:54 +02:00
parent 76175b25f5
commit 0cb6344cd5
2 changed files with 49 additions and 70 deletions
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115
Basic/FOMU_VGA/vga.v
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@@ -20,95 +20,74 @@ module vga (
output usb_dp_pu // /
);
// USB pins driven low
assign usb_dp=0;
assign usb_dn=0;
assign usb_dp_pu=0;
// USB pins driven low
assign usb_dp=0;
assign usb_dn=0;
assign usb_dp_pu=0;
wire pixclk;
wire pixclk;
// PLL: converts system clock (48 MHz)
// to pixel clock (25.125 MHz for 640x480)
// Values obtained using:
// icepll -i 48 -o 25.125
SB_PLL40_CORE #(
// PLL: converts system clock (48 MHz)
// to pixel clock (25.125 MHz for 640x480)
// Values obtained using:
// icepll -i 48 -o 25.125
SB_PLL40_CORE #(
.FEEDBACK_PATH("SIMPLE"),
.DIVR(4'b0011),
.DIVF(7'b1000010),
.DIVQ(3'b101),
.FILTER_RANGE(3'b001),
) pll (
) pll (
.REFERENCECLK (clki),
.PLLOUTCORE (pixclk),
.BYPASS (1'b0),
.RESETB (1'b1)
);
);
// video structure constants
parameter width = 640;
parameter height = 480;
parameter h_front_porch = 16;
parameter h_sync_width = 96;
parameter h_back_porch = 48;
parameter v_front_porch = 11;
parameter v_sync_width = 2;
parameter v_back_porch = 28;
// Video mode constants
parameter VGA_width = 640;
parameter VGA_height = 480;
parameter VGA_h_front_porch = 16;
parameter VGA_h_sync_width = 96;
parameter VGA_h_back_porch = 48;
parameter VGA_v_front_porch = 10;
parameter VGA_v_sync_width = 2;
parameter VGA_v_back_porch = 32;
// --------------------------------------------------------------------
parameter h_blank = h_front_porch + h_sync_width + h_back_porch;
parameter h_pixels = width + h_blank;
parameter v_blank = v_front_porch + v_sync_width + v_back_porch;
parameter v_lines = height + v_blank;
parameter hbp = h_back_porch + h_sync_width ; // end of horizontal back porch
parameter hfp = hbp + width; // beginning of horizontal front porch
parameter vbp = v_back_porch + v_sync_width ; // end of vertical back porch
parameter vfp = vbp + height; // beginning of vertical front porch
// --------------------------------------------------------------------
parameter VGA_line_width = VGA_width + VGA_h_front_porch + VGA_h_sync_width + VGA_h_back_porch;
parameter VGA_lines = VGA_height + VGA_v_front_porch + VGA_v_sync_width + VGA_v_back_porch;
// horizontal & vertical counters
reg [9:0] hc;
reg [9:0] vc;
wire in_display_zone = (vc >= vbp && vc < vfp && hc >= hbp && hc < hfp);
// frame counter
reg [15:0] frame;
// horizontal and vertical counters
always @(posedge pixclk)
begin
if (hc < h_pixels - 1) begin
hc <= hc + 1;
reg [9:0] VGA_X, VGA_Y; // current pixel coordinates
reg VGA_hSync, VGA_vSync; // horizontal and vertical synchronization
reg VGA_DrawArea; // asserted if current pixel is in drawing area
reg [15:0] VGA_frame; // frame counter
always @(posedge pixel_clk) begin
VGA_DrawArea <= (VGA_X<VGA_width) && (VGA_Y<VGA_height);
if(VGA_X==VGA_line_width-1) begin
if(VGA_Y==VGA_lines) begin
VGA_Y <= 0;
VGA_frame <= VGA_frame + 1;
end else begin
VGA_Y <= VGA_Y+1;
end
end else begin
hc <= 0;
if (vc < v_lines - 1) begin
vc <= vc + 1;
end else begin
frame <= frame + 1;
vc <= 0;
end
end
VGA_X <= VGA_X + 1;
end
VGA_hSync <= (VGA_X>=VGA_width+VGA_h_front_porch) && (VGA_X<VGA_width+VGA_h_front_porch+VGA_h_sync_width);
VGA_vSync <= (VGA_Y>=VGA_height+VGA_v_front_porch) && (VGA_Y<VGA_height+VGA_v_front_porch+VGA_v_sync_width);
end
// horizontal and vertical synchro
wire hsync = (hc < h_sync_width) ? 0:1;
wire vsync = (vc < v_sync_width) ? 0:1;
// X,Y coordinates of current pixel
wire [9:0] X = hc - hbp;
wire [9:0] Y = vc - vbp;
wire [1:0] out_color;
wire signed [9:0] dx = $signed(X) - 320;
wire signed [9:0] dy = $signed(Y) - 240;
wire signed [9:0] dx = $signed(VGA_X) - VGA_width/2;
wire signed [9:0] dy = $signed(VGA_Y) - VGA_height/2;
wire signed [15:0] R2 = dx*dx + dy*dy - $signed(frame << 6);
assign out_color = in_display_zone ? {R2[12],R2[13]} : 2'b00;
assign out_color = VGA_DrawArea ? {R2[12],R2[13]} : 2'b00;
assign user_1 = hsync;
assign user_2 = vsync;
assign user_1 = VGA_hSync;
assign user_2 = VGA_vSync;
assign user_3 = out_color[0];
assign user_4 = out_color[1];