Apple-1-HW
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verilog-apple-one
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added font and colour support at 0xC000-0xC002

This commit is contained in:
Alan Garfield 2018-02-18 17:52:19 +11:00
parent 48f6f7b78d
commit 37c3898d9f
3 changed files with 65 additions and 20 deletions
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73
rtl/apple1.v
View File

@ -48,7 +48,6 @@ module apple1 #(
output vga_red, // red VGA signal
output vga_grn, // green VGA signal
output vga_blu, // blue VGA signal
input [1:0] vga_mode, // 2-bit font mode for character rendering
input vga_cls, // clear screen button
// Debugging ports
@ -103,12 +102,15 @@ module apple1 #(
//////////////////////////////////////////////////////////////////////////
// Address Decoding
wire ram_cs = (ab[15:13] == 3'b000); // 0x0000 -> 0x1FFF
wire ram_cs = (ab[15:13] == 3'b000); // 0x0000 -> 0x1FFF
// font mode, background and foreground colour
wire vga_mode_cs = (ab[15:2] == 14'b11000000000000); // 0xC000 -> 0xC003
// RX: Either keyboard or UART input
// TX: Always VGA and UART output
wire rx_cs = (ab[15:1] == 15'b110100000001000); // 0xD010 -> 0xD011
wire tx_cs = (ab[15:1] == 15'b110100000001001); // 0xD012 -> 0xD013
wire rx_cs = (ab[15:1] == 15'b110100000001000); // 0xD010 -> 0xD011
wire tx_cs = (ab[15:1] == 15'b110100000001001); // 0xD012 -> 0xD013
// select UART on transmit but only receive when PS/2 is not selected.
wire uart_cs = tx_cs | ((~ps2_select) & rx_cs);
@ -119,8 +121,8 @@ module apple1 #(
// VGA always get characters when they are sent.
wire vga_cs = tx_cs;
wire basic_cs = (ab[15:12] == 4'b1110); // 0xE000 -> 0xEFFF
wire rom_cs = (ab[15:8] == 8'b11111111); // 0xFF00 -> 0xFFFF
wire basic_cs = (ab[15:12] == 4'b1110); // 0xE000 -> 0xEFFF
wire rom_cs = (ab[15:8] == 8'b11111111); // 0xFF00 -> 0xFFFF
//////////////////////////////////////////////////////////////////////////
// RAM and ROM
@ -196,7 +198,11 @@ module apple1 #(
);
// VGA Display interface
reg [1:0] vga_mode;
reg [2:0] fg_colour;
reg [2:0] bg_colour;
reg [1:0] font_mode;
wire [7:0] vga_mode_dout;
vga #(
.VRAM_FILENAME (VRAM_FILENAME),
.FONT_ROM_FILENAME (FONT_ROM_FILENAME)
@ -214,18 +220,59 @@ module apple1 #(
.address(ab[0]),
.w_en(we & vga_cs),
.din(dbo),
.mode(vga_mode),
.mode(font_mode),
.fg_colour(fg_colour),
.bg_colour(bg_colour),
.clr_screen(vga_cls)
);
// Handle font mode and foreground and background
// colours. This so isn't Apple One authentic, but
// it can't hurt to have some fun. :D
always @(posedge clk25 or posedge rst)
begin
if (rst)
begin
font_mode <= 2'b0;
fg_colour <= 3'd7;
bg_colour <= 3'd0;
end
else
begin
case (ab[1:0])
2'b00:
begin
vga_mode_dout = {6'b0, font_mode};
if (vga_mode_cs & we & cpu_clken)
font_mode <= dbo[1:0];
end
2'b01:
begin
vga_mode_dout = {5'b0, fg_colour};
if (vga_mode_cs & we & cpu_clken)
fg_colour <= dbo[2:0];
end
2'b10:
begin
vga_mode_dout = {5'b0, bg_colour};
if (vga_mode_cs & we & cpu_clken)
bg_colour <= dbo[2:0];
end
default:
vga_mode_dout = 8'b0;
endcase
end
end
//////////////////////////////////////////////////////////////////////////
// CPU Data In MUX
// link up chip selected device to cpu input
assign dbi = ram_cs ? ram_dout :
rom_cs ? rom_dout :
basic_cs ? basic_dout :
uart_cs ? uart_dout :
ps2kb_cs ? ps2_dout :
assign dbi = ram_cs ? ram_dout :
rom_cs ? rom_dout :
basic_cs ? basic_dout :
uart_cs ? uart_dout :
ps2kb_cs ? ps2_dout :
vga_mode_cs ? vga_mode_dout :
8'hFF;
endmodule

1
rtl/boards/ice40hx8k-b-evn/apple1_hx8k.v
View File

@ -150,7 +150,6 @@ module apple1_top #(
.vga_red(vga_red),
.vga_grn(vga_grn),
.vga_blu(vga_blu),
.vga_mode(2'b0),
.vga_cls(~clr_screen_n),
.pc_monitor(pc_monitor)
);

11
rtl/vga/vga.v
View File

@ -14,6 +14,8 @@ module vga #(
input w_en, // active high write enable strobe
input [7:0] din, // 8-bit data bus (input)
input [1:0] mode, // 2-bit mode setting for pixel doubling
input [2:0] bg_colour, // 3 bit background colour
input [2:0] fg_colour, // 3 bit foreground colour
input clr_screen // clear screen button
);
@ -202,12 +204,9 @@ module vga #(
assign font_line = v_dot;
// vga signals out to monitor
assign vga_red = font_out;
assign vga_grn = font_out;
assign vga_blu = font_out;
// make background solid blue
//assign vga_blu = (h_active & v_active) ? 1'b1 : font_out;
assign vga_red = (h_active & v_active) ? (font_out ? fg_colour[2] : bg_colour[2]) : 1'b0;
assign vga_grn = (h_active & v_active) ? (font_out ? fg_colour[1] : bg_colour[1]) : 1'b0;
assign vga_blu = (h_active & v_active) ? (font_out ? fg_colour[0] : bg_colour[0]) : 1'b0;
assign vga_h_sync = (h_cnt < h_pulse) ? 0 : 1;
assign vga_v_sync = (v_cnt < v_pulse) ? 0 : 1;