Enabling TWIM I2C on nRF52810 DK

[EthanDP]

I am currently working on enabling and transmitting/receiving data using TWIM on my nRF52810 development kit. The documentation states that in order to enable TWIM I need to provide a pointer to a structure containing the registers of the peripheral as seen below:

Unfortunately I am unsure how I can initialize this structure. Is there a function that returns an initialized NRF_TWIM_Type or do I need to manually create the structure myself. Thank you in advance and apologies if this is a dumb question

[YaroslavRakhnenko]

Hope this will help you. Mine code for nRF52810:

#include "nrf_drv_twi.h"
#include "nrfx_twim.h"

/**
 *Pins
 */
#define SCL_PIN 14
#define SDA_PIN 12

/**
 *Create TWI instance.
 */
#define TWI_INSTANCE_ID 0

static const nrfx_twim_t m_twi = NRFX_TWIM_INSTANCE(TWI_INSTANCE_ID);

/**
 * @brief  Function for i2c bus init.
 * @param  none
 * @return none
 */
void twi_init()
{
  ret_code_t err_code;

  const nrfx_twim_config_t twi_config = {
    .scl = SCL_PIN,
    .sda = SDA_PIN,
    .frequency = NRF_TWIM_FREQ_400K,
    .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
    .hold_bus_uninit = false
  };

  err_code = nrfx_twim_init(&m_twi, &twi_config, NULL, NULL); // initialize I2C
  APP_ERROR_CHECK(err_code);

  nrfx_twim_enable(&m_twi); // enable I2C
}

/**
 * @brief  Function to write one byte into XXXXX register at specified register address
 * @param  16 bit register address + 1 byte of data to be written
 * @return true if transmission was successful, otherwise false
 */
bool XXXXX_register_write_byte(uint8_t register, uint8_t value)
{
  ret_code_t err_code;

  uint8_t tx_buffer[2]; // buffer to hold registry address + data

  tx_buffer[0] = register; // register address byte
  tx_buffer[1] = value;    // value to write

  while (nrfx_twim_is_busy(&m_twi)) { }
  err_code = nrfx_twim_tx(&m_twi, your_dev_addr, tx_buffer, sizeof(tx_buffer), false);

  if (NRF_SUCCESS != err_code) {
    return false;
  }
  return true;
}

and sdk_config:

[EthanDP]

Thank you very much for this example! A couple beginner questions, when you refer to sdk_config do you mean prj.conf or is this a different configuration file that I need to find? In addition how might I use TWIM to transmit data. It seems that in your example you are sending data. Also I can't seem to import nrf_drv_twi is that part of the old sdk or is it a user created file?

[YaroslavRakhnenko]

sdk_config.h is the configuration file for the nRF SDK. If you open example-projects inside SDK you will see it

(for ex.: nRF5_SDK_17.1.0\examples\peripheral\blinky\pca10040e\blank\ses)

nrf_drv_twi maybe you don't need this. Try first with nrfx_twim_XXXX

[EthanDP]

Ah I was using the nRF Connect SDK, so unfortunately this example won't apply. Thank you very much for the help!