Hi,
I've been recently working on trying to stablish an i2c (twi) communication between my nrf52 Dev kit and a LIS3DH located in a STEVAL-IDI-003V2 board.
In this post https://devzone.nordicsemi.com/f/nordic-q-a/34710/lis2dh12-driver-issue-in-nrf-sdk-v15-0 @lhochstetter shared a successful code (thank you!).
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/** @file
* @defgroup tw_sensor_example main.c
* @{
* @ingroup nrf_twi_example
* @brief TWI Sensor Example main file.
*
* This file contains the source code for a sample application using TWI.
*
*/
#include <stdio.h>
#include "boards.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "nrf_drv_twi.h"
#include "nrf_delay.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#include "lis2dh12.h"
#include "nrf_twi_mngr.h"
/* TWI instance ID. */
#define TWI_INSTANCE_ID 0
#define MAX_PENDING_TRANSACTIONS 33
#define LIS2DH12_MIN_QUEUE_SIZE 32
NRF_TWI_MNGR_DEF(m_nrf_twi_mngr, MAX_PENDING_TRANSACTIONS, TWI_INSTANCE_ID);
NRF_TWI_SENSOR_DEF(m_nrf_twi_sensor, &m_nrf_twi_mngr, LIS2DH12_MIN_QUEUE_SIZE);
LIS2DH12_INSTANCE_DEF(m_lis2dh12, &m_nrf_twi_sensor, LIS2DH12_BASE_ADDRESS_HIGH);
static uint8_t m_sample = 0;
void print_identity(ret_code_t r, void *p_register_data)
{
NRF_LOG_INFO("Identity: %d", *((uint8_t *)p_register_data));
}
/**
* @brief Function for main application entry.
*/
int main(void)
{
uint32_t err;
nrf_drv_twi_config_t const config = {
.scl = 27,
.sda = 26,
.frequency = NRF_DRV_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_LOWEST,
.clear_bus_init = false
};
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();
NRF_LOG_INFO("TWI sensor example started.");
NRF_LOG_FLUSH();
err = nrf_twi_mngr_init(&m_nrf_twi_mngr, &config);
APP_ERROR_CHECK(err);
err = nrf_twi_sensor_init(&m_nrf_twi_sensor);
APP_ERROR_CHECK(err);
err = lis2dh12_init(&m_lis2dh12);
APP_ERROR_CHECK(err);
NRF_LOG_INFO("Here.");
NRF_LOG_FLUSH();
APP_ERROR_CHECK(err);
while (true)
{
nrf_delay_ms(500);
err = lis2dh12_who_am_i_read(&m_lis2dh12, print_identity, &m_sample);
APP_ERROR_CHECK(err);
NRF_LOG_FLUSH();
}
}
/** @} */
Right now, for me the code compiles without any errors and when loaded to the board, I get
<info> app: Identity: 0
on a PuTTY terminal.
I guess I should see the value 33, as it is the default value stored on the 0x0F WHO_AM_I register of the sensor. Am I right?
Using a osciloscope I see that the communication sequence is: [ Start - 0x19 WR - NAK - Stop ]. The 0x19 register is the first register the master writes to. In lis2dh12.h there appears
#define LIS2DH12_BASE_ADDRESS_LOW 0x18U #define LIS2DH12_BASE_ADDRESS_HIGH 0x19U
Looking at both lis2dh12 and lis3dh datasheets the registers are almost the same, and I know the 0x19U is the default address configured in the lis3dh driver. Looking at the sequence, 0x19 WR seems logical. The thing is I am not getting a response from the sensor, therefore it's no surprise to see the "Identity: 0" message on PuTTY.
I am using the lis2dh12 library but the lis3dh sensor. This may seem a problem but I can't see why it wouldn't work, as the registers that I am addressing are the same I would be addressing if I was using a lis2dh12 sensor.
Previously I tested another STEVAL-IDI003V2 sensor and I got some weird values from the sensor, but there was an existing communication between the board and the sensor. I haven't changed the wiring.
Do you think I've made a mistake using the lis2dh12 library? If so, why? Is there anything else I can check/do to solve my problem? May the sensor be damaged?
Thank you in advance,
LFanals
