1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/* cpu runs at 1mhz */
#define F_CPU 1000000
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <util/delay.h>
#include <stdio.h>
#include <stdbool.h>
#include "i2c.h"
#include "uart.h"
static void ledInit () {
/* set led1,led2 to output */
DDRB |= (1 << PB6) | (1 << PB7);
/* set led3,led4,led5,led6 to output */
DDRD |= (1 << PD2) | (1 << PD3) | (1 << PD4) | (1 << PD5);
}
/* show data with leds */
static void ledShow (const unsigned char val) {
PORTB = (PORTB & ~((1 << PB6) | (1 << PB7))) | ((val & 0x3) << PB6);
PORTD = (PORTD & ~((1 << PD2) | (1 << PD3) | (1 << PD4) | (1 << PD5))) | (((val >> 2) & 0xf) << PD2);
}
static void cpuInit () {
/* enter change prescaler mode */
CLKPR = CLKPCE << 1;
/* write new prescaler = 8 (i.e. 1Mhz clock frequency) */
CLKPR = 0b00000011;
}
volatile unsigned char count;
ISR(TIMER0_OVF_vect) {
++count;
//printf ("timer interrupt hit, count now %u\n", count);
}
#define sleepwhile(cond) \
sleep_enable (); \
while (cond) { sleep_cpu (); } \
sleep_disable ();
int main () {
cpuInit ();
ledInit ();
twInit ();
uartInit ();
set_sleep_mode (SLEEP_MODE_IDLE);
printf ("initialization done\n");
/* global interrupt enable */
sei ();
/* disable power-down-mode */
if (!twWrite (LIS302DL, LIS302DL_CTRLREG1, 0b01000111)) {
printf ("cannot start write\n");
}
sleepwhile (twr.status == TWST_WAIT);
printf ("final twi status was %i\n", twr.status);
while (1) {
uint8_t val[6];
if (!twReadMulti (LIS302DL, 0x28, val, 6)) {
printf ("cannot start read\n");
}
sleepwhile (twr.status == TWST_WAIT);
printf ("%i/%i/%i\n", (int8_t) val[1], (int8_t) val[3], (int8_t) val[5]);
count = 0;
/* set normal mode timer0 */
TCCR0A = 0;
/* io clock with 1024 prescaler */
TCCR0B = (TCCR0B & ~((1 << CS01)) | (1 << CS02) | (1 << CS00));
/* enable overflow interrupt */
TIMSK0 = (1 << TOIE0);
sleepwhile (count < 3);
/* stop timer (zero clock source) */
TCCR0B = 0;
/* XXX: why do we need the delay here? */
//_delay_ms (250);
}
/* global interrupt disable */
cli ();
while (1);
}
|
