MacPlus_MiSTer/sys/scandoubler.v
2021-03-03 17:35:46 +08:00

212 lines
4.6 KiB
Verilog

//
// scandoubler.v
//
// Copyright (c) 2015 Till Harbaum <till@harbaum.org>
// Copyright (c) 2017-2021 Alexey Melnikov
//
// This source file is free software: you can redistribute it and/or modify
// it under the terms of the GNU 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/>.
// TODO: Delay vsync one line
module scandoubler #(parameter LENGTH, parameter HALF_DEPTH)
(
// system interface
input clk_vid,
input hq2x,
// shifter video interface
input ce_pix,
input hs_in,
input vs_in,
input hb_in,
input vb_in,
input [DWIDTH:0] r_in,
input [DWIDTH:0] g_in,
input [DWIDTH:0] b_in,
// output interface
output ce_pix_out,
output reg hs_out,
output vs_out,
output hb_out,
output vb_out,
output [DWIDTH:0] r_out,
output [DWIDTH:0] g_out,
output [DWIDTH:0] b_out
);
localparam DWIDTH = HALF_DEPTH ? 3 : 7;
reg [7:0] pix_len = 0;
wire [7:0] pl = pix_len + 1'b1;
reg [7:0] pix_in_cnt = 0;
wire [7:0] pc_in = pix_in_cnt + 1'b1;
reg [7:0] pixsz, pixsz2, pixsz4 = 0;
reg ce_x4i, ce_x1i;
always @(posedge clk_vid) begin
reg old_ce, valid, hs;
if(~&pix_len) pix_len <= pl;
if(~&pix_in_cnt) pix_in_cnt <= pc_in;
ce_x4i <= 0;
ce_x1i <= 0;
// use such odd comparison to place ce_x4 evenly if master clock isn't multiple of 4.
if((pc_in == pixsz4) || (pc_in == pixsz2) || (pc_in == (pixsz2+pixsz4))) ce_x4i <= 1;
old_ce <= ce_pix;
if(~old_ce & ce_pix) begin
if(valid & ~hb_in & ~vb_in) begin
pixsz <= pl;
pixsz2 <= {1'b0, pl[7:1]};
pixsz4 <= {2'b00, pl[7:2]};
end
pix_len <= 0;
valid <= 1;
end
hs <= hs_in;
if((~hs & hs_in) || (pc_in >= pixsz)) begin
ce_x4i <= 1;
ce_x1i <= 1;
pix_in_cnt <= 0;
end
if(hb_in | vb_in) valid <= 0;
end
reg req_line_reset;
reg [DWIDTH:0] r_d, g_d, b_d;
always @(posedge clk_vid) begin
if(ce_x1i) begin
req_line_reset <= hb_in;
r_d <= r_in;
g_d <= g_in;
b_d <= b_in;
end
end
Hq2x #(.LENGTH(LENGTH), .HALF_DEPTH(HALF_DEPTH)) Hq2x
(
.clk(clk_vid),
.ce_in(ce_x4i),
.inputpixel({b_d,g_d,r_d}),
.disable_hq2x(~hq2x),
.reset_frame(vb_in),
.reset_line(req_line_reset),
.ce_out(ce_x4o),
.read_y(sd_line),
.hblank(hbo[0]&hbo[8]),
.outpixel({b_out,g_out,r_out})
);
reg [7:0] pix_out_cnt = 0;
wire [7:0] pc_out = pix_out_cnt + 1'b1;
reg ce_x4o, ce_x2o;
always @(posedge clk_vid) begin
reg hs;
if(~&pix_out_cnt) pix_out_cnt <= pc_out;
ce_x4o <= 0;
ce_x2o <= 0;
// use such odd comparison to place ce_x4 evenly if master clock isn't multiple of 4.
if((pc_out == pixsz4) || (pc_out == pixsz2) || (pc_out == (pixsz2+pixsz4))) ce_x4o <= 1;
if( pc_out == pixsz2) ce_x2o <= 1;
hs <= hs_out;
if((~hs & hs_out) || (pc_out >= pixsz)) begin
ce_x2o <= 1;
ce_x4o <= 1;
pix_out_cnt <= 0;
end
end
reg [1:0] sd_line;
reg [3:0] vbo;
reg [3:0] vso;
reg [8:0] hbo;
always @(posedge clk_vid) begin
reg [31:0] hcnt;
reg [30:0] sd_hcnt;
reg [30:0] hs_start, hs_end;
reg [30:0] hde_start, hde_end;
reg hs, hb;
if(ce_x4o) begin
hbo[8:1] <= hbo[7:0];
end
// output counter synchronous to input and at twice the rate
sd_hcnt <= sd_hcnt + 1'd1;
if(sd_hcnt == hde_start) begin
sd_hcnt <= 0;
vbo[3:1] <= vbo[2:0];
end
if(sd_hcnt == hs_end) begin
sd_line <= sd_line + 1'd1;
if(&vbo[3:2]) sd_line <= 1;
vso[3:1] <= vso[2:0];
end
if(sd_hcnt == hde_start)hbo[0] <= 0;
if(sd_hcnt == hde_end) hbo[0] <= 1;
// replicate horizontal sync at twice the speed
if(sd_hcnt == hs_end) hs_out <= 0;
if(sd_hcnt == hs_start) hs_out <= 1;
hs <= hs_in;
hb <= hb_in;
hcnt <= hcnt + 1'd1;
if(hb && !hb_in) begin
hde_start <= hcnt[31:1];
hbo[0] <= 0;
hcnt <= 0;
sd_hcnt <= 0;
vbo <= {vbo[2:0],vb_in};
end
if(!hb && hb_in) hde_end <= hcnt[31:1];
// falling edge of hsync indicates start of line
if(hs && !hs_in) begin
hs_end <= hcnt[31:1];
vso[0] <= vs_in;
end
// save position of rising edge
if(!hs && hs_in) hs_start <= hcnt[31:1];
end
assign vs_out = vso[3];
assign ce_pix_out = hq2x ? ce_x4o : ce_x2o;
//Compensate picture shift after HQ2x
assign vb_out = vbo[3];
assign hb_out = hbo[6];
endmodule