Hi everyone and thanks in advance.
I'm new to the NRF52 SDK enviroment and I've been having some trouble with the I2C/TWI configuration. The SDK we are using in the v12.3.0 and I've use the TWI_sensor example and modifying it to suit my application.
The code is this:
#include <stdio.h>
#include "boards.h"
#include "app_util_platform.h"
#include "app_error.h"
#include "nrf_drv_twi.h"
#include "nrf_delay.h"
#define NRF_LOG_MODULE_NAME "APP"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
/* TWI instance ID. */
#define TWI_INSTANCE_ID 0
// MPU9250 Addresses definition
#define MPU9250_ADDRESS 0x68
#define MAG_ADDRESS 0x0C
#define ACC_CONF 28
#define GYRO_FULL_SCALE_250_DPS 0x00
#define GYRO_FULL_SCALE_500_DPS 0x08
#define GYRO_FULL_SCALE_1000_DPS 0x10
#define GYRO_FULL_SCALE_2000_DPS 0x18
#define ACC_FULL_SCALE_2_G 0x00
#define ACC_FULL_SCALE_4_G 0x08
#define ACC_FULL_SCALE_8_G 0x10
#define ACC_FULL_SCALE_16_G 0x18
#define ACC_SCALE ACC_FULL_SCALE_16_G
/* Indicates if operation on TWI has ended. */
static volatile bool m_xfer_done = false;
/* TWI instance. */
static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);
/* Buffer for samples read from temperature sensor. */
static uint8_t m_sample;
__STATIC_INLINE void data_handler(uint8_t temp)
{
NRF_LOG_INFO("Temperature: %d Celsius degrees.\r\n", temp);
}
/**
* @brief TWI events handler.
*/
void print_errorcode(uint32_t error_code)
{
/* No human readable form found */
NRF_LOG_INFO("\r\nFunction return code: (%x)", error_code);
}
void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
switch (p_event->type)
{
case NRF_DRV_TWI_EVT_DONE:
if (p_event->xfer_desc.type == NRF_DRV_TWI_XFER_RX)
{
data_handler(m_sample);
}
m_xfer_done = true;
break;
default:
break;
}
}
/**
* @brief UART initialization.
*/
void twi_init (void)
{
ret_code_t err_code;
const nrf_drv_twi_config_t twi_lm75b_config = {
.scl = ARDUINO_SCL_PIN,
.sda = ARDUINO_SDA_PIN,
.frequency = NRF_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH,
.clear_bus_init = false
};
err_code = nrf_drv_twi_init(&m_twi, &twi_lm75b_config, twi_handler, NULL);
APP_ERROR_CHECK(err_code);
nrf_drv_twi_enable(&m_twi);
NRF_LOG_INFO("\r I2C configurado \r\n");
NRF_LOG_INFO("\r \r\n");
}
/**
* @brief Function for reading data from temperature sensor.
*/
void initmpu9250(void)
{
ret_code_t err_code;
uint8_t reg[2] = {0x1C,ACC_SCALE};
//NRF_LOG_INFO("\r Valor registro %x %x\r \n",reg[0], reg[1]);
//NRF_LOG_FLUSH();
err_code = nrf_drv_twi_tx(&m_twi,MPU9250_ADDRESS, reg, 2, false);
APP_ERROR_CHECK(err_code);
//print_errorcode(err_code);
while (m_xfer_done == false);
}
uint32_t nrf_drv_mpu_read_registers(uint8_t reg, uint8_t * p_data, uint32_t length)
{
uint32_t err_code;
//uint32_t timeout = MPU_TWI_TIMEOUT;
//uint8_t buf[6];
err_code = nrf_drv_twi_tx(&m_twi, MPU9250_ADDRESS, ®, 1, false);
if(err_code != NRF_SUCCESS) return err_code;
err_code = nrf_drv_twi_rx(&m_twi, MPU9250_ADDRESS, p_data, length);
if(err_code != NRF_SUCCESS) return err_code;
// timeout = MPU_TWI_TIMEOUT;
// while((!twi_rx_done) && --timeout);
// if(!timeout) return NRF_ERROR_TIMEOUT;
// twi_rx_done = false;
return err_code;
}
/**
* @brief Function for main application entry.
*/
int main(void)
{
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_INFO("\r Inicio programa\r \n");
NRF_LOG_FLUSH();
twi_init();
initmpu9250();
NRF_LOG_INFO("\r MPU init done\r \n");
NRF_LOG_FLUSH();
while (true)
{
NRF_LOG_INFO("\r loop \r\n");
NRF_LOG_FLUSH();
nrf_delay_ms(500);
/* do
{
__WFE();
}while (m_xfer_done == false);
*/
//read_sensor_data();
}
}
/** @} */
The code is quite simple, but I can not capture any TWI/I2C frame. Clock line is Pull-up but seems to be not working and SDA generating the same pulses, here is a screenshot:
Also, the code stop working right after enters the initmpu9250() function, so that's why I think is something wrong in my initialization rutine.
Do you see any error in the code?
Thanks, Borja.
