I've been trying to use nRF52 (PCA10040 board) with SDK 12 to read data from max30102 through I2C.
I used non-blocking read and this is twi init function and event hander:
void twi_init (void)
{
ret_code_t err_code;
const nrf_drv_twi_config_t twi_config = {
.scl = DEVICE_SCL_PIN, // 25
.sda = DEVICE_SDA_PIN, // 26
.frequency = NRF_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH
};
err_code = nrf_drv_twi_init(&twi_instance, &twi_config, twi_handler, NULL);
APP_ERROR_CHECK(err_code);
nrf_drv_twi_enable(&twi_instance);
}
void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
switch(p_event->type)
{
case NRF_DRV_TWI_EVT_DONE:
m_xfer_done = true;
break;
case NRF_DRV_TWI_EVT_ADDRESS_NACK:
break;
case NRF_DRV_TWI_EVT_DATA_NACK:
break;
default:
break;
}
}
However, when I used the following code to read from one of its registers, I couldn't get expected value.
reg_addr = 0xFF; // register 0xFF stores fixed part ID 0x15
device_address = 0x57;
uint8_t part_id[2];
m_xfer_done = false;
err_code = nrf_drv_twi_tx(&twi_instance, device_address, ®_addr, 1, true);
if(NRF_SUCCESS == err_code) { // always SUCCESS
m_xfer_done = false;
err_code = nrf_drv_twi_rx(&twi_instance, device_address, part_id, 1);
// ALWAYS error with value 0x11
printf("\t\t ** (0x%2X 0x%2X) 0x%2X\r\n", part_id[0], part_id[1], err_code);
} else {
printf("\t\t\tnrf_drv_twi_rx error 0x%X\r\n", err_code);
}
The device address by data sheet is 0xAF; somehow I was suggested ([link text])(devzone.nordicsemi.com/.../) to use 0x57. But I cannot get value 0x15.
I have successfully tested the sensor with Arduino UNO. What did I miss on nRF52?
