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| Source at commit 63a4b895d3d7da5a8b71ab383976ae835db52e99 created 10 years 11 months ago. By Werner Almesberger, tornado/cpu/cpu.sch (CON3): nISP and nRESET were swapped | |
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| 1 | /* |
| 2 | * fw/image.c - Image sweep |
| 3 | * |
| 4 | * Written 2012 by Werner Almesberger |
| 5 | * Copyright 2012 Werner Almesberger |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | |
| 14 | #include <stdbool.h> |
| 15 | #include <stdint.h> |
| 16 | |
| 17 | #include <avr/io.h> |
| 18 | #include <avr/interrupt.h> |
| 19 | |
| 20 | #include "image.h" |
| 21 | #include "sweep.h" |
| 22 | |
| 23 | |
| 24 | volatile bool sweeping = 0; |
| 25 | |
| 26 | |
| 27 | static volatile uint32_t t_up; /* uptime, in timer ticks (wraps in 4295 s) */ |
| 28 | static volatile uint32_t t_sw; /* cumulative number of timer ticks in sweep */ |
| 29 | |
| 30 | static uint16_t wait_periods; /* number of periods to wait before image */ |
| 31 | static uint16_t wait_period; /* ticks in wait period */ |
| 32 | static uint16_t wait_short; /* ticks to wait after periods */ |
| 33 | |
| 34 | static uint16_t pixel_ticks; /* number of ticks per pixel */ |
| 35 | static const struct line *curr_line; |
| 36 | static const struct line *end_line; |
| 37 | static bool forward; |
| 38 | |
| 39 | |
| 40 | ISR(TIMER1_OVF_vect) |
| 41 | { |
| 42 | uint16_t t; |
| 43 | |
| 44 | /* update the time counters */ |
| 45 | |
| 46 | t = ICR1; |
| 47 | t_sw += t; |
| 48 | t_up += t; |
| 49 | |
| 50 | /* if at the end of the image, only update the time */ |
| 51 | |
| 52 | if (curr_line == end_line) { |
| 53 | PORTB &= 0x3f; |
| 54 | PORTC = 0; |
| 55 | PORTD = 0; |
| 56 | ICR1 = 0xffff; |
| 57 | sweeping = 0; |
| 58 | return; |
| 59 | } |
| 60 | |
| 61 | /* wait before starting the image */ |
| 62 | |
| 63 | if (wait_periods) { |
| 64 | if (!--wait_periods) |
| 65 | ICR1 = wait_short; |
| 66 | return; |
| 67 | } |
| 68 | |
| 69 | /* if done, lights out and slow down */ |
| 70 | |
| 71 | /* output the next line */ |
| 72 | |
| 73 | set_line(*curr_line); |
| 74 | |
| 75 | /* move to the next line */ |
| 76 | |
| 77 | if (forward) |
| 78 | curr_line++; |
| 79 | else |
| 80 | curr_line--; |
| 81 | |
| 82 | /* wait until the next pixel */ |
| 83 | |
| 84 | ICR1 = pixel_ticks; |
| 85 | } |
| 86 | |
| 87 | |
| 88 | uint32_t uptime_irq(void) |
| 89 | { |
| 90 | uint32_t t; |
| 91 | |
| 92 | t = t_up+TCNT1; |
| 93 | if (TIFR1 & TOV1) |
| 94 | t += ICR1; |
| 95 | return t; |
| 96 | } |
| 97 | |
| 98 | |
| 99 | uint32_t uptime(void) |
| 100 | { |
| 101 | uint32_t a, b; |
| 102 | uint16_t d; |
| 103 | |
| 104 | do { |
| 105 | cli(); |
| 106 | a = t_up; |
| 107 | d = TCNT1; |
| 108 | cli(); |
| 109 | b = t_up; |
| 110 | sei(); |
| 111 | } |
| 112 | while (a != b); |
| 113 | return a+d; |
| 114 | } |
| 115 | |
| 116 | |
| 117 | void sweep_image(const struct sweep *sweep) |
| 118 | { |
| 119 | uint32_t t; |
| 120 | |
| 121 | /* calculate start time */ |
| 122 | |
| 123 | t = uptime(); |
| 124 | if (sweep->start_ticks <= t) |
| 125 | return; |
| 126 | t = sweep->start_ticks-t; |
| 127 | |
| 128 | TCCR1B = 0; /* stop the timer */ |
| 129 | |
| 130 | cli(); |
| 131 | |
| 132 | /* shut down all the LEDs, in case we're still in a sweep */ |
| 133 | |
| 134 | PORTB &= 0x3f; |
| 135 | PORTC = 0; |
| 136 | PORTD = 0; |
| 137 | |
| 138 | /* image pointers and sweep direction */ |
| 139 | |
| 140 | forward = sweep->forward; |
| 141 | if (forward) { |
| 142 | curr_line = image+sweep->left; |
| 143 | end_line = image+sweep->right+1; |
| 144 | } else { |
| 145 | curr_line = image+sweep->right; |
| 146 | end_line = image+sweep->left-1; |
| 147 | } |
| 148 | |
| 149 | /* timing parameters */ |
| 150 | |
| 151 | pixel_ticks = sweep->pixel_ticks; |
| 152 | wait_periods = t >> 16; |
| 153 | if (wait_periods) { |
| 154 | wait_short = t; |
| 155 | wait_period = 0xffff; |
| 156 | |
| 157 | /* |
| 158 | * Make sure we have plenty of time to update ICR1 after an |
| 159 | * interrupt. |
| 160 | */ |
| 161 | if (wait_short < 256) { |
| 162 | wait_period -= 128; |
| 163 | wait_short += wait_periods << 7; |
| 164 | } |
| 165 | ICR1 = wait_period; |
| 166 | } else { |
| 167 | ICR1 = t; |
| 168 | } |
| 169 | |
| 170 | /* prepare the hardware timer */ |
| 171 | |
| 172 | t_sw = 0; /* reset the time */ |
| 173 | TCNT1 = 0; |
| 174 | TIFR1 = 1 << TOV1; /* clear interrupt */ |
| 175 | |
| 176 | /* start the timer */ |
| 177 | |
| 178 | TCCR1B = |
| 179 | 1 << WGM13 | /* WG Mode 14, continued */ |
| 180 | 1 << WGM12 | |
| 181 | 1 << CS11; /* clkIO/8 */ |
| 182 | |
| 183 | sweeping = 1; |
| 184 | |
| 185 | sei(); |
| 186 | } |
| 187 | |
| 188 | |
| 189 | void sweep_init(void) |
| 190 | { |
| 191 | TCCR1A = |
| 192 | 1 << WGM11; /* WG Mode 14 (Fast PWM to ICR1) */ |
| 193 | |
| 194 | TCNT1 = 0; |
| 195 | |
| 196 | TIMSK1 = 1 << TOIE1; /* enable timer interrupts */ |
| 197 | } |
| 198 | |
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