NRFX_TWI_TX returning error 0x01

[danved]

When I run nrfx_twi_tx i get the error code 0x01, and I can't find out why. I'm running SDK15.0 on PCA10040, using ses.

My init function looks like this:

void twi_init (uint8_t scl, uint8_t sda)
{
    nrfx_err_t err_code;

    const nrfx_twi_config_t twi_config = {
       .scl                = scl,
       .sda                = sda,
       .frequency          = NRF_TWI_FREQ_100K,
       .interrupt_priority = NRFX_TWI_DEFAULT_CONFIG_IRQ_PRIORITY,
       .hold_bus_uninit    = NRFX_TWI_DEFAULT_CONFIG_HOLD_BUS_UNINIT
    };

    err_code = nrfx_twi_init(&g_twi, &twi_config, NULL, NULL);
    APP_ERROR_CHECK(err_code);
    
    #ifdef DEBUG

    if(err_code != NRFX_SUCCESS){
      NRF_LOG_ERROR("ERROR INITIALIZING NRFX_TWI");
    }
    else{
      NRF_LOG_INFO("INITIALIZED NRFX_TWI");
    }
    NRF_LOG_FLUSH();
    #endif



    nrfx_twi_enable(&g_twi);

}

The initialization is successful.

Then I try to send some data, and get 0x01 error code. The code:

void ssd1306_send_command(uint8_t command){
  nrfx_err_t error = NRFX_SUCCESS;

  uint8_t data[2];

  data[0] = 0x00;    // Co = 0, D/C = 0  CONTROL BYTE
  data[1] = command;


  error = nrfx_twi_tx(&g_twi, SSD1306_TWI_ADDRESS, data, (sizeof(data)), true);
  
  #ifdef DEBUG
  if (error = !NRFX_SUCCESS){
 
     NRF_LOG_ERROR("Error sending command to display. Errorcode: %x", error);
     NRF_LOG_FLUSH();
  }
  else{
    NRF_LOG_INFO("Sent 0x%x to display", command);
    NRF_LOG_FLUSH();
  }
  #endif
}

I'm new to using the nrfx drivers, but have used nrf_drv_twi before with success. Any help would be appreciated.

[MartinBL]

Hi,

Have you tried stepping through nrfx_twi_tx() with your debugger to see where the value 0x1 comes from?

[danved]

Hi, I have discovered the error. It was a stupid mistake from my side. In my error checking if statement i assign error to !NRFX_SUCCESS instead of checking if error =! NRF_SUCCESS.