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author | Lars-Dominik Braun <lars@6xq.net> | 2014-03-10 17:28:07 +0100 |
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committer | Lars-Dominik Braun <lars@6xq.net> | 2014-04-22 16:51:13 +0200 |
commit | e69b2bc45ff0940b475a1832d25e051240fbda32 (patch) | |
tree | e4847c55b06e4aa2ee71e2dab05663bd6be34757 /accel.c | |
parent | 8493da1edbc863cd8525bebca4ab86ef1888c232 (diff) | |
download | hourglass-e69b2bc45ff0940b475a1832d25e051240fbda32.tar.gz hourglass-e69b2bc45ff0940b475a1832d25e051240fbda32.tar.bz2 hourglass-e69b2bc45ff0940b475a1832d25e051240fbda32.zip |
Initial accel implementation
Diffstat (limited to 'accel.c')
-rw-r--r-- | accel.c | 88 |
1 files changed, 88 insertions, 0 deletions
@@ -0,0 +1,88 @@ +#include <stdio.h> +#include <string.h> +#include <avr/io.h> +#include <avr/interrupt.h> +#include <avr/sleep.h> + +#include "i2c.h" +#include "accel.h" + +/* device address */ +#define LIS302DL 0b00111000 +/* registers */ +#define LIS302DL_WHOAMI 0xf +#define LIS302DL_CTRLREG1 0x20 +#define LIS302DL_UNUSED1 0x28 + +#define sleepwhile(cond) \ + sleep_enable (); \ + while (cond) { sleep_cpu (); } \ + sleep_disable (); + +/* the first interrupt is lost */ +static volatile bool drdy = true; +/* 0, 2 and 4 are zero, as they contain the dummy register’s content */ +static volatile int8_t val[6] = {0, 0, 0, 0, 0, 0}; +/* currently reading from i2c */ +static bool reading = false; + +#warning "wrong interrupt" +/* data ready interrupt + */ +ISR(PCINT1_vect) { + drdy = true; +} + +void accelInit () { + /* 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 accelStart () { + /* configuration: + * disable power-down-mode + * defaults + * data ready interrupt on int2 + */ + uint8_t data[] = {0b01000111, 0b0, 0b00100000}; + + if (!twRequest (TWM_WRITE, LIS302DL, LIS302DL_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 accelProcess () { + if (reading) { + if (twr.status == TWST_OK) { + /* new data transfered */ + reading = false; + return true; + } else if (twr.status == TWST_ERR) { + printf ("accel i2c error\n"); + reading = false; + } + } else { + if (drdy && twr.status != TWST_WAIT) { + /* new data available in device buffer and bus is free, we are + * reading the registers inbetween out_x/y/z and ignore them */ + if (!twRequest (TWM_READ, LIS302DL, LIS302DL_UNUSED1, (uint8_t *) val, 6)) { + printf ("cannot start read\n"); + } else { + drdy = false; + reading = true; + } + } + } + + return false; +} + |