uzix/zx-sizif-xxs
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replace composite video output implementation

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New one is borrowed from Speccy 2010 project. It's have a much, much
better output quality in price of increased FPGA resources usage.
This commit is contained in:
UzixLS
2021-11-15 22:57:36 +03:00
parent f30d6faa6d
commit e33bd97a7e
12 changed files with 645 additions and 566 deletions
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49
fpga/rtl/top.sv
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@ -22,9 +22,8 @@ module zx_ula(
output reg n_int,
output n_nmi,
output reg [5:0] luma,
output reg [2:0] chroma,
output reg csync,
output [7:0] composite,
input [1:0] reserv,
output snd_l,
output snd_r,
@ -41,10 +40,15 @@ module zx_ula(
/* CLOCK */
wire clk28 = clk_in;
wire clk40;
wire clk20;
wire clk168;
wire rst_n;
pll pll0(.inclk0(clk_in), .c0(clk40), .c1(clk20), .locked(rst_n));
pll pll0(.inclk0(clk_in), .c0(clk168), .locked(rst_n));
reg [1:0] clk168_en42_cnt = 0;
reg clk168_en42;
always @(posedge clk168) begin
clk168_en42 <= clk168_en42_cnt == 2'b00;
clk168_en42_cnt <= clk168_en42_cnt + 1'b1;
end
/* SHARED DEFINITIONS */
@ -104,9 +108,8 @@ end
/* SCREEN CONTROLLER */
wire blink;
wire [2:0] screen_border = {border[2] ^ ~sd_cs, border[1] ^ magic_beeper, border[0]};
wire [2:0] r, g;
wire [1:0] b;
wire hsync;
wire [5:0] r, g, b;
wire hsync, vsync, csync0;
wire screen_contention, port_ff_active;
wire [14:0] screen_addr;
wire [5:0] up_ink_addr, up_paper_addr;
@ -124,8 +127,8 @@ screen screen0(
.r(r),
.g(g),
.b(b),
.csync(csync),
.vsync(),
.csync(csync0),
.vsync(vsync),
.hsync(hsync),
.fetch_allow((!bus.iorq && !bus.mreq && !bus.m1) || bus.rfsh || clkwait),
@ -157,21 +160,17 @@ screen screen0(
/* VIDEO OUTPUT */
always @*
luma <= 2*r + 5*g + b;
wire [2:0] chroma0;
chroma_gen #(.CLK_FREQ(40_000_000)) chroma_gen1(
.cg_clock(clk40),
.cg_rgb({|g,|r,|b}),
.cg_hsync(hsync),
.cg_enable(1'b1),
.cg_pnsel(1'b0),
.cg_out(chroma0)
vencode vencode(
.clk(clk168),
.clk_en(clk168_en42),
.videoR(r),
.videoG(g),
.videoB(b),
.videoHS_n(hsync),
.videoVS_n(vsync),
.videoPS_n(csync0),
.videoV(composite)
);
assign chroma[0] = (chroma0[1])? chroma0[0] : 1'bz;
assign chroma[1] = (chroma0[2])? chroma0[0] : 1'bz;
assign chroma[2] = (chroma0[2])? chroma0[0] : 1'bz;
/* PS/2 KEYBOARD */