TWI - NRF_ERROR_BUSY with nRF52832 and s132

[Ander GB]

Hi,

I have recently inherited a project from a former worker. The code intends to read data from a peripherial through TWI (the peripherial is a Si7053 digital temperature sensors from Silicon Labs).

I am using the dev board PCA10040 v 1.1.1 2017.1. I am compiling the code with gcc and using Eclipse Mars.2 (4.5.2).

I was not getting the expected values form the readings so first I tried the peripherial in a Arduino Board and it works properly (peripherial issue discarded). Then I debbuged the app with gdb and I found the problem:

the nrf_drv_twi_rx (infocenter.nordicsemi.com/index.jsp function is returning a NRF_ERROR_BUSY, so I guess it is not reading properly.

This is the function:

bool twi_read_register (uint8_t * reg, uint8_t * p_data, uint8_t length_reg, uint8_t length_data) {

	// Variables
    uint32_t err_code;
    uint32_t timeout = TWI_TIMEOUT;

    // Enable TWI
    nrf_drv_twi_enable(&m_twi_instance);

    // Transfer the address of the device to read data from it
    err_code = nrf_drv_twi_tx(&m_twi_instance, ADDRESS, reg, length_reg, false);

    // Check if error in transfer
    if(err_code != NRF_SUCCESS) return false;

    // Wait until twi_tx done flag change or timeout
    while((!twi_tx_done) && --timeout);
    if(!timeout) return false;

    twi_tx_done = false;

    // Receive data from the sensor
    err_code = nrf_drv_twi_rx(&m_twi_instance, ADDRESS, p_data, length_data);

    // Check if error when receiving
    if(err_code != NRF_SUCCESS) return false;

    // Wait until twi_rx done flag change or timeout
    timeout = TWI_TIMEOUT;
    while((!twi_rx_done) && --timeout);
    if(!timeout) return false;

    twi_rx_done = false;

    return true;
}

//ADRESS = 0x40
//reg = 0xE3
//length_reg = 1
//length_data = 2

I am quite lost. Any help would be welcome.

[Jørgen Holmefjord]

Sorry about the slow reply. Have you tried removing the timeout handling in your twi_read_register() function? It does not seem like you are checking the return value from the calls to twi_read_register(), so if a timeout happens and the function returns false, the application can still try to start a new transfer. Unfortunately, I do not have the correct sensor to test this.