Revision f8c1522b
Added bom sending code (not yet tested)
| scout_avr/bom/bom.c | ||
|---|---|---|
| 1 | 1 |
#include <stdint.h> |
| 2 | 2 |
#include <avr/io.h> |
| 3 | 3 |
#include <avr/interrupt.h> |
| 4 |
#include <util/delay.h> |
|
| 5 | 4 |
#include "twi.h" |
| 6 | 5 |
#include "bomi2c.h" |
| 7 | 6 |
|
| ... | ... | |
| 13 | 12 |
char last_bit; |
| 14 | 13 |
char count; |
| 15 | 14 |
uint16_t data; |
| 15 |
volatile char currently_sending; |
|
| 16 |
char sending_counter; |
|
| 17 |
uint16_t sending_data; |
|
| 16 | 18 |
|
| 17 | 19 |
#define READ_BIT(pin, bit) (((pin) >> bit) & 1) |
| 18 | 20 |
#define SET_BIT(pin, bit) ((pin) |= (1 << (bit))) |
| 19 |
#define RESET_BIT(pin, bit) ((pin) &= ~(1 << (bit))) |
|
| 21 |
#define PRESCALAR 8 |
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| 22 |
#define TIME_US(us) (F_CPU * (us) / 1000000 / PRESCALAR) |
|
| 20 | 23 |
|
| 21 | 24 |
static void send_bit(char bit); |
| 22 | 25 |
|
| ... | ... | |
| 55 | 58 |
//EIMSK |= _BV(INT0); |
| 56 | 59 |
|
| 57 | 60 |
// setup timer 0 |
| 58 |
//TCCR0B |= _BV(CS01); |
|
| 61 |
TCCR0B |= _BV(CS01); |
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| 62 |
TIMSK |= _BV(OCIE0A); |
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| 63 |
|
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// setup timer 1 for output |
|
| 65 |
GTCCR |= _BV(COM1B1); // Set pin3 low when timer1 matches match b |
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| 66 |
OCR1B = TIME_US(320); // Set match b to fire every 320 us |
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| 67 |
TIMSK |= _BV(OCIE1A); // Enable interrupt for match a |
|
| 68 |
TCCR1 |= _BV(CTC1); // Enables resetting timer1 after matches match a |
|
| 59 | 69 |
|
| 60 | 70 |
// setup output pin |
| 61 | 71 |
SET_BIT(DDRD, 5); |
| ... | ... | |
| 64 | 74 |
bom_start(); |
| 65 | 75 |
} |
| 66 | 76 |
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| 77 |
|
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| 78 |
|
|
| 67 | 79 |
ISR(TIMER0_COMPA_vect) {
|
| 68 | 80 |
|
| 69 | 81 |
char this_bit = READ_BIT(PIND, PD2); |
| ... | ... | |
| 88 | 100 |
} |
| 89 | 101 |
} |
| 90 | 102 |
|
| 91 |
static void send_data(uint16_t data) {
|
|
| 92 |
for (int i = 14; i >= 0; i--) {
|
|
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send_bit((data >> i) & 1); |
|
| 94 |
} |
|
| 95 |
send_bit(0); |
|
| 103 |
static void send_next_bit() {
|
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char next_bit = sending_data >> (14-counter) & 1; |
|
| 105 |
char ocr_temp next_bit ? TIME_US(2000) : TIME_US(1000); |
|
| 106 |
OCR1A = ocr_temp; |
|
| 107 |
OCR1C = ocr_temp; |
|
| 108 |
SET_BIT(PORTD, PD5); |
|
| 96 | 109 |
} |
| 97 | 110 |
|
| 98 |
static void send_bit(char bit) {
|
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| 99 |
SET_BIT(PORTD, PD5); |
|
| 100 |
_delay_us(320); |
|
| 101 |
RESET_BIT(PORTD, PD5); |
|
| 102 |
if (bit) {
|
|
| 103 |
_delay_us(1680); |
|
| 111 |
ISR(TIMER1_COMPA_vect) {
|
|
| 112 |
if (++counter > 15) {
|
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| 113 |
currently_sending = 0; |
|
| 114 |
TCCR1 &= ~0x0F; // Stop the timer without clearing CTC1 |
|
| 104 | 115 |
} else {
|
| 105 |
_delay_us(680);
|
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| 116 |
send_next_bit();
|
|
| 106 | 117 |
} |
| 107 | 118 |
} |
| 108 | 119 |
|
| 120 |
static void send_data(uint16_t data) {
|
|
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sending_data = data; |
|
| 122 |
sending_counter = 0; |
|
| 123 |
currently_sending = 1; |
|
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send_next_bit(); |
|
| 125 |
TCCR1 |= _BV(CS12); // Set prescalar to 8 and start timer |
|
| 126 |
while (currently_sending) { }
|
|
| 127 |
} |
|
| 109 | 128 |
int main() {
|
| 110 | 129 |
bom_init(); |
| 111 | 130 |
for (;;) {
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