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 26 #define ZERO_LENGTH 1 /* pixels */ 27 28 /* 24MHz cycle measurements. */ 29 30 #define HFREQ_LIMIT 643 31 #define HSYNC_START 460 32 #define HSYNC_LIMIT 64 33 #define HSYNC_END (HSYNC_START + HSYNC_LIMIT) 34 35 /* Horizontal lines, back porch end. */ 36 37 #define VISIBLE_START 70 38 #define VFP_START (VISIBLE_START + 2 * LINE_COUNT) 39 40 /* Horizontal lines, front porch end. */ 41 42 #define VSYNC_START 620 43 44 /* Horizontal lines, back porch start. */ 45 46 #define VSYNC_END 622 47 48 #define SCREEN_BASE 256 49 #define SCREEN_SIZE (40 * 1024) 50 #define SCREEN_LIMIT (SCREEN_BASE + SCREEN_SIZE) 51 52 #define SCREEN_BASE_KSEG0 (KSEG0_BASE + SCREEN_BASE) 53 #define SCREEN_LIMIT_KSEG0 (KSEG0_BASE + SCREEN_LIMIT) 54 55 #endif /* __VGA_H__ */