1 /* 2 * Generate a VGA signal using a PIC32 microcontroller. 3 * 4 * Copyright (C) 2017, 2018 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software: you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation, either version 3 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #ifndef __VGA_H__ 21 #define __VGA_H__ 22 23 #define LINE_LENGTH 160 /* pixels */ 24 #define LINE_COUNT 256 /* distinct display lines */ 25 #define LINE_MULTIPLIER 2 26 27 /* 48MHz cycle measurements. */ 28 29 #define HFREQ_LIMIT 1286 30 #define HSYNC_START 920 31 #define HSYNC_LIMIT 128 32 #define HSYNC_END (HSYNC_START + HSYNC_LIMIT) 33 34 /* Horizontal lines, back porch end. */ 35 36 #define VISIBLE_START 70 37 #define VFP_START (VISIBLE_START + LINE_MULTIPLIER * LINE_COUNT) 38 39 /* Horizontal lines, front porch end. */ 40 41 #define VSYNC_START 620 42 43 /* Horizontal lines, back porch start. */ 44 45 #define VSYNC_END 622 46 47 /* Framebuffer properties. */ 48 49 #define SCREEN_SIZE (LINE_LENGTH * LINE_COUNT) 50 51 /* Transfer and pixel allocation properties. */ 52 53 #define TRANSFER_CELL_SIZE LINE_LENGTH 54 #define CELL_SIZE LINE_LENGTH 55 56 #endif /* __VGA_H__ */