| paul@37 | 1 | /* |
| paul@37 | 2 | * Generate a VGA signal using a PIC32 microcontroller. |
| paul@37 | 3 | * |
| paul@37 | 4 | * Copyright (C) 2017, 2018 Paul Boddie <paul@boddie.org.uk> |
| paul@37 | 5 | * |
| paul@37 | 6 | * This program is free software: you can redistribute it and/or modify |
| paul@37 | 7 | * it under the terms of the GNU General Public License as published by |
| paul@37 | 8 | * the Free Software Foundation, either version 3 of the License, or |
| paul@37 | 9 | * (at your option) any later version. |
| paul@37 | 10 | * |
| paul@37 | 11 | * This program is distributed in the hope that it will be useful, |
| paul@37 | 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| paul@37 | 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| paul@37 | 14 | * GNU General Public License for more details. |
| paul@37 | 15 | * |
| paul@37 | 16 | * You should have received a copy of the GNU General Public License |
| paul@37 | 17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| paul@37 | 18 | */ |
| paul@37 | 19 | |
| paul@37 | 20 | |
| paul@37 | 21 | #include "pic32_c.h" |
| paul@37 | 22 | #include "init.h" |
| paul@37 | 23 | #include "debug.h" |
| paul@41 | 24 | |
| paul@41 | 25 | /* Specific functionality. */ |
| paul@41 | 26 | |
| paul@37 | 27 | #include "main.h" |
| paul@47 | 28 | #include "devconfig.h" |
| paul@37 | 29 | #include "vga.h" |
| paul@41 | 30 | #include "display.h" |
| paul@49 | 31 | #include "display_config.h" |
| paul@50 | 32 | #include "vga_display.h" |
| paul@37 | 33 | |
| paul@37 | 34 | |
| paul@41 | 35 | |
| paul@37 | 36 | /* Blink an attached LED with delays implemented using a loop. */ |
| paul@37 | 37 | |
| paul@37 | 38 | static void blink(uint32_t delay, uint32_t port, uint32_t pins) |
| paul@37 | 39 | { |
| paul@37 | 40 | uint32_t counter; |
| paul@37 | 41 | |
| paul@37 | 42 | /* Clear outputs (LED). */ |
| paul@37 | 43 | |
| paul@37 | 44 | CLR_REG(port, pins); |
| paul@37 | 45 | |
| paul@37 | 46 | while (1) |
| paul@37 | 47 | { |
| paul@37 | 48 | counter = delay; |
| paul@37 | 49 | |
| paul@37 | 50 | while (counter--) __asm__(""); /* retain loop */ |
| paul@37 | 51 | |
| paul@37 | 52 | /* Invert outputs (LED). */ |
| paul@37 | 53 | |
| paul@37 | 54 | INV_REG(port, pins); |
| paul@37 | 55 | } |
| paul@37 | 56 | } |
| paul@37 | 57 | |
| paul@37 | 58 | |
| paul@37 | 59 | |
| paul@37 | 60 | /* Main program. */ |
| paul@37 | 61 | |
| paul@37 | 62 | void main(void) |
| paul@37 | 63 | { |
| paul@37 | 64 | init_memory(); |
| paul@37 | 65 | init_pins(); |
| paul@37 | 66 | init_outputs(); |
| paul@37 | 67 | |
| paul@37 | 68 | unlock_config(); |
| paul@37 | 69 | config_oc(); |
| paul@37 | 70 | config_uart(); |
| paul@37 | 71 | lock_config(); |
| paul@37 | 72 | |
| paul@37 | 73 | init_dma(); |
| paul@57 | 74 | |
| paul@57 | 75 | /* Initialise VGA output structures with two line channels and an initiating |
| paul@57 | 76 | channel. */ |
| paul@57 | 77 | |
| paul@56 | 78 | init_vga(&display_config, 2, T2); |
| paul@37 | 79 | |
| paul@37 | 80 | /* Peripheral relationships: |
| paul@37 | 81 | |
| paul@37 | 82 | Timer2 -> OC1 |
| paul@37 | 83 | -> OC2 (vertical sync region) |
| paul@46 | 84 | -> DMA1: zerodata -> PORTB (visible region) |
| paul@37 | 85 | | |
| paul@46 | 86 | Timer3 -> DMA0: linedata -> PORTB |
| paul@46 | 87 | Timer3 -> DMA2: linedata -> PORTB |
| paul@37 | 88 | | |
| paul@46 | 89 | Timer3 -> DMA3: zerodata -> PORTB |
| paul@37 | 90 | */ |
| paul@37 | 91 | |
| paul@56 | 92 | /* Configure VGA output transfer details along with a timer and output |
| paul@56 | 93 | compare units for horizontal and vertical sync. */ |
| paul@46 | 94 | |
| paul@56 | 95 | vga_configure_transfer(T3, PORTB); |
| paul@56 | 96 | vga_configure_sync(1, 2, 2); |
| paul@37 | 97 | |
| paul@37 | 98 | /* Configure a timer for line data transfers. */ |
| paul@37 | 99 | |
| paul@37 | 100 | timer_init(3, 0, 1); |
| paul@37 | 101 | timer_on(3); |
| paul@37 | 102 | |
| paul@47 | 103 | uart_init(1, FPB, 115200); |
| paul@37 | 104 | uart_on(1); |
| paul@37 | 105 | |
| paul@56 | 106 | test_linedata(&display_config); |
| paul@56 | 107 | |
| paul@37 | 108 | interrupts_on(); |
| paul@37 | 109 | |
| paul@37 | 110 | blink(3 << 24, PORTA, 1 << 3); |
| paul@37 | 111 | } |
| paul@37 | 112 | |
| paul@37 | 113 | |
| paul@37 | 114 | |
| paul@37 | 115 | /* Exception and interrupt handlers. */ |
| paul@37 | 116 | |
| paul@37 | 117 | void exception_handler(void) |
| paul@37 | 118 | { |
| paul@37 | 119 | blink(3 << 12, PORTA, 1 << 3); |
| paul@37 | 120 | } |
| paul@37 | 121 | |
| paul@37 | 122 | void interrupt_handler(void) |
| paul@37 | 123 | { |
| paul@37 | 124 | uint32_t ifs; |
| paul@37 | 125 | |
| paul@37 | 126 | /* Check for a OC1 interrupt condition. */ |
| paul@37 | 127 | |
| paul@37 | 128 | ifs = REG(OCIFS) & OC_INT_FLAGS(1, OCxIF); |
| paul@37 | 129 | |
| paul@37 | 130 | if (ifs) |
| paul@37 | 131 | { |
| paul@50 | 132 | vga_interrupt_handler(); |
| paul@37 | 133 | CLR_REG(OCIFS, ifs); |
| paul@37 | 134 | } |
| paul@37 | 135 | } |
| paul@37 | 136 | |
| paul@37 | 137 | |
| paul@37 | 138 | |
| paul@37 | 139 | /* Peripheral pin configuration. */ |
| paul@37 | 140 | |
| paul@37 | 141 | void config_oc(void) |
| paul@37 | 142 | { |
| paul@37 | 143 | /* Map OC1 to RPA0. */ |
| paul@37 | 144 | |
| paul@37 | 145 | REG(RPA0R) = 0b0101; /* RPA0R<3:0> = 0101 (OC1) */ |
| paul@37 | 146 | |
| paul@37 | 147 | /* Map OC2 to RPA1. */ |
| paul@37 | 148 | |
| paul@37 | 149 | REG(RPA1R) = 0b0101; /* RPA1R<3:0> = 0101 (OC2) */ |
| paul@37 | 150 | } |
| paul@37 | 151 | |
| paul@37 | 152 | void config_uart(void) |
| paul@37 | 153 | { |
| paul@37 | 154 | /* Map U1RX to RPB13. */ |
| paul@37 | 155 | |
| paul@37 | 156 | REG(U1RXR) = 0b0011; /* U1RXR<3:0> = 0011 (RPB13) */ |
| paul@37 | 157 | |
| paul@37 | 158 | /* Map U1TX to RPB15. */ |
| paul@37 | 159 | |
| paul@37 | 160 | REG(RPB15R) = 0b0001; /* RPB15R<3:0> = 0001 (U1TX) */ |
| paul@37 | 161 | |
| paul@37 | 162 | /* Set RPB13 to input. */ |
| paul@37 | 163 | |
| paul@37 | 164 | SET_REG(TRISB, 1 << 13); |
| paul@37 | 165 | } |
