Hi, I am wroking on nRF52840 Evaluation board where I am using p0.16 and p0.17 as SDA and SCL respectively using I2c mechanism and trying to read the device id, but it seems to be not working as i am getting the output as no device found?

[Manoj S]

#if TWI0_ENABLED
#define TWI_INSTANCE_ID 0
#elif TWI1_ENABLED
#define TWI_INSTANCE_ID 1
#endif

/* Number of possible TWI addresses. */
#define TWI_ADDRESSES 127

/* TWI instance. */
static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);

/**
* @brief TWI initialization.
*/
void twi_init (void)
{
ret_code_t err_code;

const nrf_drv_twi_config_t twi_config = {
.scl =  NRF_GPIO_PIN_MAP(0,17),
.sda = NRF_GPIO_PIN_MAP(0,16),
.frequency = NRF_DRV_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH,
.clear_bus_init = false
};

err_code = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);
APP_ERROR_CHECK(err_code);

nrf_drv_twi_enable(&m_twi);

}

int main(void)
{
ret_code_t err_code;
uint8_t address;
uint8_t sample_data;
bool detected_device = false;

APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();

NRF_LOG_INFO("TWI scanner started.");
NRF_LOG_FLUSH();
twi_init();

for (address = 1; address <= TWI_ADDRESSES; address++)
{
err_code = nrf_drv_twi_rx(&m_twi, address, &sample_data, sizeof(sample_data));
if (err_code == NRF_SUCCESS)
{
detected_device = true;
NRF_LOG_INFO("TWI device detected at address 0x%x.", address);
}
NRF_LOG_FLUSH();
}

if (!detected_device)
{
NRF_LOG_INFO("No device was found.");
NRF_LOG_FLUSH();
}

}

[Jared]

Hi,

Do you see the any activity on either the SCL or SDA line? 

[Manoj S]

Nope

[Jared]

Hi,

P0.16 and P0.17 is already used as CS and LED on the devkit. Try switching pins to for example P0.30 and P0.31

regards

Jared