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 92 /* pixels */ 24 #define LINE_COUNT 128 /* distinct display lines */ 25 #define LINE_MULTIPLIER 4 26 27 #define ZERO_LENGTH 1 /* pixels */ 28 29 /* 24MHz cycle measurements. */ 30 31 #define HFREQ_LIMIT 643 32 #define HSYNC_START 508 33 #define HSYNC_LIMIT 40 34 #define HSYNC_END (HSYNC_START + HSYNC_LIMIT) 35 36 /* Horizontal lines, back porch end. */ 37 38 #define VISIBLE_START 70 39 #define VFP_START (VISIBLE_START + LINE_MULTIPLIER * LINE_COUNT) 40 41 /* Horizontal lines, front porch end. */ 42 43 #define VSYNC_START 620 44 45 /* Horizontal lines, back porch start. */ 46 47 #define VSYNC_END 622 48 49 /* Framebuffer properties. */ 50 51 #define SCREEN_SIZE (LINE_LENGTH * LINE_COUNT) 52 53 /* Transfer and pixel allocation properties. */ 54 55 #define TRANSFER_CELL_SIZE 1 56 #define CELL_SIZE 1 57 58 #endif /* __VGA_H__ */
