Enabling TWIM I2C on nRF52810 DK

RE: Enabling TWIM I2C on nRF52810 DK

EthanDP — Thu, 30 Jun 2022 18:32:20 GMT

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

RE: Enabling TWIM I2C on nRF52810 DK

Jørgen Holmefjord — Wed, 29 Jun 2022 15:53:17 GMT

Hi,

NRF_TWIM_Type is defined in chip header file in the MDK (e.g nrf52810.h for nRF52810 chip).

I'm not sure exactly which API you are referring to in your initial post, but it sounds like you are using nRF Connect SDK from your comment about prj.conf.

Zephyr provides an I2C driver API, which you can use if you do not want to write your own TWIM driver. This uses nrfx_twi(m) internally, and should use TWIM/EasyDMA if you set CONFIG_NRFX_TWIMx in your prj.conf file.

Best regards,
Jørgen

RE: Enabling TWIM I2C on nRF52810 DK

YaroslavRakhnenko — Wed, 29 Jun 2022 07:51:31 GMT

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

RE: Enabling TWIM I2C on nRF52810 DK

EthanDP — Tue, 28 Jun 2022 20:08:34 GMT

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?

RE: Enabling TWIM I2C on nRF52810 DK

YaroslavRakhnenko — Tue, 28 Jun 2022 19:31:54 GMT

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: