root / toolbox / led.c @ 1085ef77
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| 1 | dc472500 | Tom Mullins | #include "led.h" |
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| 2 | #include <avr/io.h> |
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| 3 | 1b054655 | Tom Mullins | #include <avr/interrupt.h> |
| 4 | dc472500 | Tom Mullins | |
| 5 | #define PRESCALE 64 |
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| 6 | #define CLOCK_SEL 3 |
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| 7 | |||
| 8 | /* F_CPU / PRESCALE = OCR * 1000 + ERROR */
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| 9 | #define OCR (F_CPU / PRESCALE / 1000UL) |
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| 10 | #define ERROR (F_CPU / PRESCALE - OCR * 1000UL) |
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| 11 | |||
| 12 | 1085ef77 | Tom Mullins | char blink_count;
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| 13 | enum color_t blink_color;
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| 14 | uint16_t blink_period; |
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| 15 | dc472500 | Tom Mullins | |
| 16 | uint16_t ms; |
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| 17 | uint16_t error; |
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| 18 | |||
| 19 | 1085ef77 | Tom Mullins | static void led_color(enum color_t color) { |
| 20 | switch (color) {
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| 21 | case OFF:
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| 22 | led_off(); |
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| 23 | break;
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| 24 | case RED:
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| 25 | led_red(); |
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| 26 | break;
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| 27 | case YELLOW:
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| 28 | led_yellow(); |
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| 29 | break;
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| 30 | case GREEN:
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| 31 | led_green(); |
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| 32 | break;
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| 33 | } |
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| 34 | } |
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| 35 | |||
| 36 | dc472500 | Tom Mullins | static void blink() { |
| 37 | 1085ef77 | Tom Mullins | blink_count--; |
| 38 | if (blink_count % 2) { |
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| 39 | led_color(blink_color); |
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| 40 | dc472500 | Tom Mullins | } else {
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| 41 | led_off(); |
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| 42 | } |
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| 43 | } |
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| 44 | |||
| 45 | ISR(TIMER0_COMPA_vect) {
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| 46 | error += ERROR; |
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| 47 | if (error >= 1000) { |
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| 48 | error -= 1000;
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| 49 | } else {
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| 50 | ms++; |
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| 51 | 1085ef77 | Tom Mullins | if (ms == blink_period) {
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| 52 | dc472500 | Tom Mullins | blink(); |
| 53 | 1085ef77 | Tom Mullins | if (blink_count == 0) { |
| 54 | dc472500 | Tom Mullins | TCCR0B = 0;
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| 55 | } |
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| 56 | ms = 0;
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| 57 | } |
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| 58 | } |
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| 59 | } |
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| 60 | |||
| 61 | 1085ef77 | Tom Mullins | void led_blink_start(unsigned int period_ms, char n_times, enum color_t color) { |
| 62 | |||
| 63 | dc472500 | Tom Mullins | ms = 0;
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| 64 | error = 0;
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| 65 | 1085ef77 | Tom Mullins | |
| 66 | blink_count = n_times*2-1; |
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| 67 | blink_period = period_ms/2;
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| 68 | blink_color = color; |
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| 69 | led_color(color); |
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| 70 | |||
| 71 | dc472500 | Tom Mullins | OCR0A = OCR; |
| 72 | 1b054655 | Tom Mullins | TIMSK = _BV(OCIE0A); |
| 73 | dc472500 | Tom Mullins | TCCR0A = _BV(WGM01); |
| 74 | TCCR0B = CLOCK_SEL; |
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| 75 | 1085ef77 | Tom Mullins | |
| 76 | dc472500 | Tom Mullins | } |
| 77 | |||
| 78 | char led_blink_done() {
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| 79 | 1085ef77 | Tom Mullins | return blink_count == 0; |
| 80 | dc472500 | Tom Mullins | } |