diff options
Diffstat (limited to 'gyro.c')
-rw-r--r-- | gyro.c | 77 |
1 files changed, 77 insertions, 0 deletions
@@ -0,0 +1,77 @@ +#include <stdio.h> +#include <avr/io.h> +#include <avr/interrupt.h> +#include <avr/sleep.h> + +#include "i2c.h" +#include "gyro.h" + +/* device address */ +#define L3GD20 0b11010100 +/* registers */ +#define L3GD20_WHOAMI 0xf +#define L3GD20_CTRLREG1 0x20 +#define L3GD20_CTRLREG3 0x22 +#define L3GD20_CTRLREG4 0x23 + +#define sleepwhile(cond) \ + sleep_enable (); \ + while (cond) { sleep_cpu (); } \ + sleep_disable (); + +/* the first interrupt is lost */ +volatile bool drdy = true; +volatile int16_t val[3] = {0, 0, 0}; + +/* data ready interrupt + */ +ISR(PCINT0_vect) { + drdy = true; +} + +void gyroInit () { + /* set PB1 to input, with pull-up */ + DDRB = (DDRB & ~((1 << PB1))); + PORTB = (PORTB | (1 << PB1)); + /* enable interrupt PCI0 */ + PCICR = (1 << PCIE0); + /* enable interrupts on PB1/PCINT1 */ + PCMSK0 = (1 << 1); +} + +/* XXX: make nonblocking */ +void gyroStart () { + /* configuration: + * disable power-down-mode + * defaults + * enable drdy interrupt + * select 500dps + */ + uint8_t data[] = {0b00001111, 0b0, 0b00001000, 0b00010000}; + + if (!twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data, + sizeof (data)/sizeof (*data))) { + printf ("cannot start write\n"); + } + sleepwhile (twr.status == TWST_WAIT); + printf ("final twi status was %i\n", twr.status); +} + +bool gyroRead () { + if (drdy) { + drdy = false; + + if (!twRequest (TWM_READ, L3GD20, 0x28, (uint8_t *) val, 6)) { + printf ("cannot start read\n"); + } + + return true; + } else { + return false; + } +} + +volatile const int16_t *gyroGet () { + return val; +} + |