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8bitworkshop/presets/verilog/ram1.v
2018-02-09 00:11:36 -06:00

86 lines
1.7 KiB
Verilog

`include "hvsync_generator.v"
`include "digits10.v"
module RAM_1KB(clk, addr, din, dout, we);
input clk; // clock
input [9:0] addr; // 10-bit address
input [7:0] din; // 8-bit data input
output [7:0] dout; // 8-bit data output
input we; // write enable
reg [7:0] mem [1024]; // 1024x8 bit memory
always @(posedge clk) begin
if (we) // if write enabled
mem[addr] <= din; // write memory from din
dout <= mem[addr]; // read memory to dout
end
endmodule
module test_framebuf_top(clk, reset, hsync, vsync, rgb);
input clk, reset;
output hsync, vsync;
output [2:0] rgb;
wire display_on;
wire [8:0] hpos;
wire [8:0] vpos;
wire [9:0] ram_addr;
wire [7:0] ram_read;
reg [7:0] ram_write;
reg ram_writeenable = 0;
RAM_1KB ram(
.clk(clk),
.dout(ram_read),
.din(ram_write),
.addr(ram_addr),
.we(ram_writeenable)
);
hvsync_generator hvsync_gen(
.clk(clk),
.reset(reset),
.hsync(hsync),
.vsync(vsync),
.display_on(display_on),
.hpos(hpos),
.vpos(vpos)
);
wire [4:0] row = vpos[7:3];
wire [4:0] col = hpos[7:3];
wire [3:0] digit = ram_read[3:0];
wire [2:0] yofs = vpos[2:0];
wire [2:0] xofs = hpos[2:0];
wire [4:0] bits;
assign ram_addr = {row,col};
digits10_case numbers(
.digit(digit),
.yofs(yofs),
.bits(bits)
);
wire r = display_on && 0;
wire g = display_on && bits[~xofs];
wire b = display_on && 0;
assign rgb = {b,g,r};
always @(posedge clk)
if (display_on && vpos[2:0] == 7)
case (hpos[2:0])
6: begin
ram_write <= (ram_read + 1);
ram_writeenable <= 1;
end
7: ram_writeenable <= 0;
endcase
endmodule