TWI Fails to receive/send

RE: TWI Fails to receive/send

Jørgen Holmefjord — Wed, 05 Apr 2017 13:46:57 GMT

Error code 0x03 means "NRF_ERROR_INTERNAL - If an error was detected by hardware." This can be caused by many things. Could you try adding a short delay between twi_init and the first tx?

RE: TWI Fails to receive/send

XploD — Tue, 04 Apr 2017 18:35:04 GMT

I've revised my question with new code.

RE: TWI Fails to receive/send

Jørgen Holmefjord — Tue, 04 Apr 2017 10:39:16 GMT

According to the datasheet of ADXL345, it requires the master to write the register address before reading.

RE: TWI Fails to receive/send

djqtsg — Tue, 04 Apr 2017 10:28:43 GMT

Is it not true nrf_drv_twi_tx() must be called first before rx?

RE: TWI Fails to receive/send

Jørgen Holmefjord — Tue, 04 Apr 2017 09:31:12 GMT

Have you checked what the error code returned from nrf_drv_twi_rx() is?

RE: TWI Fails to receive/send

djqtsg — Tue, 04 Apr 2017 06:46:56 GMT

Have you studied carefully the sample TWI code? I guess you are making wrong use of API.

The following is my working code for reading one byte of data from register 0x0A of an I2C device with I2C write/read address I2C_WRITE_ADDR/I2C_READ_ADDR

uint8_t reg_addr = 0x0A;	// register address
err = nrf_drv_twi_tx(&m_twi, I2C_WRITE_ADDR, &reg_addr, 1, true);
//APP_ERROR_CHECK(err_code);
if(NRF_SUCCESS != err) {
	...	// return false; ??
}
			
uint8_t p_data[1];
err = nrf_drv_twi_rx(&m_twi, I2C_READ_ADDR, p_data, 1);
if(NRF_SUCCESS != err) {
	...	// return false; ??
}
    return true;