How to use TWI with BLE to transfer MPU6050 data

[harlek]

Hi,

I am developing on NRF51822 custom board but I had a problem on how to init TWI driver to communicate with MPU6050.

In short, when receiving a BLE_CONNECTED event I trigger a TIMER wih rearming every 2second. Within the timer_timeout_handler I use nrf_drv_twi_tx() and nrf_drv_twi_rx() function to performing I2C READ transaction with NON-BLOCKING mode

However, it seems that my board keeps reseting when I waits for the twi_handler() event. Here is my init code for TWI:

const nrf_drv_twi_config_t twi_mpu6050_config = {
   .scl                = 3,
   .sda                = 4,
   .frequency          = NRF_TWI_FREQ_400K,
   .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
   .clear_bus_init     = false
};

err_code = nrf_drv_twi_init(&m_twi_master, &twi_mpu6050_config, twi_handler, NULL);
APP_ERROR_CHECK(err_code);

nrf_drv_twi_enable(&m_twi_master);

And the twi_tx and twi_rx looks like:

err_code = nrf_drv_twi_rx(&m_twi_master, MP6050_ADDR, &m_sample, sizeof(m_sample));
err_code = nrf_drv_twi_tx(&m_twi_master, MP6050_ADDR, &reg, 1, true);

NOTE:

• I also made sure that the err_code was always 0

• When I switched back to BLOCKING MODE, this time my board seemed to be loop inside nrf_drv_twi_tx() function

Could you please give me some advice or preference to my case?

Thank you very much, Harlek.

[harlek]

I made a reference on this EXAMPLE and start writing my own project. But twi_tx always TIMEOUT and the twi_handler() function was never called.

Do you know any idea why?

I also attached the code main.c

[MartinBL]

Hi,

This is probably related to your interrupt priorities. See these posts:

Can ble_nus_string_send() be called from a TWI callback?

SPI hangs within RTC CC callback closed

[harlek]

Thank you so much for the great support, Martin.

It is really helpful