lis3dh/example/filter-reference.c

73 lines
1.7 KiB
C

#define _GNU_SOURCE
#include <unistd.h> /* usleep() */
#include <stdio.h>
#include "lis3dh.h"
#include "i2c.h"
int main() {
lis3dh_t lis;
lis.dev.init = i2c_init;
lis.dev.read = i2c_read;
lis.dev.write = i2c_write;
lis.dev.sleep = usleep;
lis.dev.deinit = i2c_deinit;
/* initialise LIS3DH struct */
if (lis3dh_init(&lis)) {
/* error handling */
}
/* reset device just in case */
if (lis3dh_reset(&lis)) {
/* error handling */
}
lis.cfg.mode = LIS3DH_MODE_HR;
lis.cfg.range = LIS3DH_FS_2G;
lis.cfg.rate = LIS3DH_ODR_100_HZ;
/* normal mode */
lis.cfg.filter.mode = LIS3DH_FILTER_MODE_REFERENCE;
/* 3dB cutoff freq (~ ODR) */
lis.cfg.filter.cutoff = LIS3DH_FILTER_CUTOFF_8;
/* Output [x y z] data is calculated as the difference between the
* measured acceleration and the value stored in REFERENCE.
* signed 7-bit int, 1 LSb value depends on FS.
* FS_2G: ~ 16mg per 1 LSb
* FS_4G: ~ 31mg per 1 LSb
* FS_8G: ~ 63mg per 1 LSb
* FS_16G: ~127mg per 1 LSb */
/* @ 2G,
* To have the output data be referenced to 0.8g:
* => 800 mg / 16 mg = 50 */
/* to reference -0.8g simply put -50 */
lis.cfg.reference = 50;
/* write config to device */
if (lis3dh_configure(&lis)) {
/* error handling */
}
/* Do not read REFERENCE */
for ( ;; ) {
/* read an [x y z] accel set. Filter is applied */
if (lis3dh_read(&lis)) {
/* error handling */
}
printf("x: %4.d, y: %4.d, z: %4.d\n", lis.acc.x, lis.acc.y, lis.acc.z);
usleep(5000); /* 5 ms */
}
/* deinitalise struct */
if (lis3dh_deinit(&lis)) {
/* error handling */
}
return 0;
}