scoutos / scout_avr / bom / bom.c @ f8c1522b
History | View | Annotate | Download (2.54 KB)
1 |
#include <stdint.h> |
---|---|
2 |
#include <avr/io.h> |
3 |
#include <avr/interrupt.h> |
4 |
#include "twi.h" |
5 |
#include "bomi2c.h" |
6 |
|
7 |
#define QUEUE_SIZE 64 |
8 |
|
9 |
uint16_t queue[QUEUE_SIZE]; |
10 |
int queue_idx;
|
11 |
|
12 |
char last_bit;
|
13 |
char count;
|
14 |
uint16_t data; |
15 |
volatile char currently_sending; |
16 |
char sending_counter;
|
17 |
uint16_t sending_data; |
18 |
|
19 |
#define READ_BIT(pin, bit) (((pin) >> bit) & 1) |
20 |
#define SET_BIT(pin, bit) ((pin) |= (1 << (bit))) |
21 |
#define PRESCALAR 8 |
22 |
#define TIME_US(us) (F_CPU * (us) / 1000000 / PRESCALAR) |
23 |
|
24 |
static void send_bit(char bit); |
25 |
|
26 |
static void slave_tx(void) { |
27 |
twi_transmit((uint8_t*)queue, queue_idx * sizeof(queue[0])); |
28 |
queue_idx = 0;
|
29 |
} |
30 |
|
31 |
static void slave_rx(uint8_t *buf, int len) { |
32 |
if (len > 0) { |
33 |
switch (buf[0]) { |
34 |
case BOM_I2C_SEND:
|
35 |
// TODO
|
36 |
break;
|
37 |
} |
38 |
} |
39 |
} |
40 |
|
41 |
static void bom_start(void) { |
42 |
data = 0;
|
43 |
count = 0;
|
44 |
last_bit = 1;
|
45 |
// TODO disable interrupt
|
46 |
// TODO start timer
|
47 |
} |
48 |
|
49 |
static void bom_stop(void) { |
50 |
// TODO stop timer
|
51 |
// TODO restart INT0
|
52 |
} |
53 |
|
54 |
static void bom_init(void) { |
55 |
|
56 |
// setup INT0
|
57 |
//EICRA |= _BV(ISC01) | _BV(ISC00);
|
58 |
//EIMSK |= _BV(INT0);
|
59 |
|
60 |
// setup timer 0
|
61 |
TCCR0B |= _BV(CS01); |
62 |
TIMSK |= _BV(OCIE0A); |
63 |
|
64 |
// setup timer 1 for output
|
65 |
GTCCR |= _BV(COM1B1); // Set pin3 low when timer1 matches match b
|
66 |
OCR1B = TIME_US(320); // Set match b to fire every 320 us |
67 |
TIMSK |= _BV(OCIE1A); // Enable interrupt for match a
|
68 |
TCCR1 |= _BV(CTC1); // Enables resetting timer1 after matches match a
|
69 |
|
70 |
// setup output pin
|
71 |
SET_BIT(DDRD, 5);
|
72 |
|
73 |
//sei();
|
74 |
bom_start(); |
75 |
} |
76 |
|
77 |
|
78 |
|
79 |
ISR(TIMER0_COMPA_vect) { |
80 |
|
81 |
char this_bit = READ_BIT(PIND, PD2);
|
82 |
|
83 |
if (this_bit == 0) { |
84 |
if (last_bit == 0) { |
85 |
bom_stop(); |
86 |
} |
87 |
} else {
|
88 |
data = data << 1 | (~last_bit & 1); |
89 |
count++; |
90 |
} |
91 |
|
92 |
last_bit = this_bit; |
93 |
|
94 |
if (count == 15) { |
95 |
if (queue_idx < QUEUE_SIZE) {
|
96 |
queue[queue_idx] = data; |
97 |
queue_idx++; |
98 |
} |
99 |
bom_stop(); |
100 |
} |
101 |
} |
102 |
|
103 |
static void send_next_bit() { |
104 |
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); |
109 |
} |
110 |
|
111 |
ISR(TIMER1_COMPA_vect) { |
112 |
if (++counter > 15) { |
113 |
currently_sending = 0;
|
114 |
TCCR1 &= ~0x0F; // Stop the timer without clearing CTC1 |
115 |
} else {
|
116 |
send_next_bit(); |
117 |
} |
118 |
} |
119 |
|
120 |
static void send_data(uint16_t data) { |
121 |
sending_data = data; |
122 |
sending_counter = 0;
|
123 |
currently_sending = 1;
|
124 |
send_next_bit(); |
125 |
TCCR1 |= _BV(CS12); // Set prescalar to 8 and start timer
|
126 |
while (currently_sending) { }
|
127 |
} |
128 |
int main() {
|
129 |
bom_init(); |
130 |
for (;;) {
|
131 |
send_data(45243);
|
132 |
_delay_ms(100);
|
133 |
} |
134 |
} |
135 |
|
136 |
ISR(INT0_vect) { |
137 |
bom_start(); |
138 |
} |