129 lines
3.5 KiB
C
129 lines
3.5 KiB
C
#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <math.h>
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#include "lis3dh.h"
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#include "interrupt.h"
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#include "i2c.h"
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#define GPIO_INTERRUPT_PIN_INT1 12
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int main() {
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lis3dh_t lis;
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/* set fn ptrs to rw on bus (i2c or SPI) */
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lis.dev.init = i2c_init;
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lis.dev.read = i2c_read;
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lis.dev.write = i2c_write;
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lis.dev.sleep = usleep;
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lis.dev.deinit = i2c_deinit;
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/* initialise LIS3DH struct */
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if (lis3dh_init(&lis)) {
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/* error handling */
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}
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/* reset device just in case */
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if (lis3dh_reset(&lis)) {
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/* error handling */
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}
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/* register interrupt */
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if (int_register(GPIO_INTERRUPT_PIN_INT1)) {
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/* error handling */
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}
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/* set up config */
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lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.range = LIS3DH_FS_2G;
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lis.cfg.rate = LIS3DH_ODR_400_HZ;
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/* no filter because we want the 'absolute' experienced acceleration */
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lis.cfg.pin1.ia1 = 1; /* enable INT1 through pin1 */
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lis.cfg.int1.latch = 1; /* latch interrupt until INT1_SRC is read */
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/* enable all the low directions */
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/* this works because the low directions are compared to -threshold,
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and are below it at rest, and greater than it at free-fall,
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while the opposite is true for the high directions. */
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lis.cfg.int1.xl = 1;
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lis.cfg.int1.yl = 1;
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lis.cfg.int1.zl = 1;
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/* AND interrupt mode */
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lis.cfg.int1.aoi = 1;
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lis.cfg.int1.en_6d = 0;
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/* 1 LSb = 16 mg @ FS_2G
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* Due to inherent problems with accuracy and timing, you should use a "free-fall window",
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* rather than setting the threshold to 0. AN3308 pg 27 recommends at or below 350mg for all axes,
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* to be considered as being in a state of free-fall, but the gradual return to experiencing
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* 1g in free-fall is not discussed.
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*
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* 350/16 ~= 20
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*/
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lis.cfg.int1_ths = 20;
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/*
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* Duration time is measured in N/ODR where:
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* --- N = The content of the intX_dur integer
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* --- ODR = the data rate, eg 100, 400...
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* [ODR] [1 LSb in milliseconds]
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* 400 2.5
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*
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* At 400 ODR,
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* 30 ms = 30/2.5 = 12
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*/
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lis.cfg.int1_dur = 12;
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/* write device config */
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if (lis3dh_configure(&lis)) {
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/* error handling */
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}
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/* read INT1_SRC to clear previous interrupts, if any */
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if (lis3dh_read_int1(&lis)) {
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/* error handling */
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}
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for ( ;; ) {
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/* poll interrupt on INT1 pin */
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if (int_poll(GPIO_INTERRUPT_PIN_INT1)) {
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/* error handling */
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}
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/* read INT1_SRC when interrupt has fired */
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if (lis3dh_read_int1(&lis)) {
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/* error handling */
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}
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/* only print if IA=1 */
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if (LIS3DH_INT_SRC_IA(lis.src.int1)) {
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/* print received interrupt .. */
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printf("IA=%d ZH=%d ZL=%d YH=%d YL=%d XH=%d XL=%d\n",
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LIS3DH_INT_SRC_IA(lis.src.int1),
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LIS3DH_INT_SRC_Z_HIGH(lis.src.int1),
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LIS3DH_INT_SRC_Z_LOW(lis.src.int1),
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LIS3DH_INT_SRC_Y_HIGH(lis.src.int1),
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LIS3DH_INT_SRC_Y_LOW(lis.src.int1),
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LIS3DH_INT_SRC_X_HIGH(lis.src.int1),
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LIS3DH_INT_SRC_X_LOW(lis.src.int1));
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}
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}
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/* unregister interrupt */
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if (int_unregister(GPIO_INTERRUPT_PIN_INT1)) {
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/* error handling */
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}
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/* deinitalise struct */
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if (lis3dh_deinit(&lis)) {
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/* error handling */
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}
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return 0;
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} |