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