RE: Serial display of data using TWI

Jared — Mon, 25 May 2020 07:58:55 GMT

Where do you print "sample_data", and when is read_data_sensor() called? Have you checked that the NRF_DRV_TWI_EVT_DONE event has been generated before you read? If yes, then I suggest using the debugger to check what is stored in sample_data after a rx operation.

RE: Serial display of data using TWI

Alanarf — Wed, 20 May 2020 10:30:18 GMT

Hi Jared, thanks for reply.

Yes, I am using the recommended settings.
NRF LOG outputs are visible on putty, but not the data.

TWI handle is called, but then nothing is shown on putty.

<Note about the sensor>
I need to set measurement mode on the chip, which i do in the set_mode() function by setting CCS811_REG_MEAS_MODE register to 1, this will set the sensor to measure values every second.
<...>

Anyway, I removed the lines 17 to 25 from the function set_mode(), and created a new function called read_data_sensor(), which prints the strange value of 253 on putty. You can see the code for read_data_sensor() bellow

static void read_sensor_data()
{
    ret_code_t err_code;
	m_xfer_done = false;
	
	//Setting sensor reading register 
    uint8_t reg = CCS811_REG_RAW_DATA;
	
    err_code = nrf_drv_twi_tx(&m_twi, DEVICE_ID, &reg, sizeof(reg), false);
    APP_ERROR_CHECK(err_code);
	if (err_code == NRF_SUCCESS){ //	If the procedure was successful.
			NRF_LOG_INFO("TX OK");
		} 

 
    err_code = nrf_drv_twi_rx(&m_twi, DEVICE_ID, &sample_data, sizeof(sample_data));
	APP_ERROR_CHECK(err_code);
	nrf_delay_ms(200);
	
			
        if (err_code == NRF_SUCCESS){ //	If the procedure was successful.
			NRF_LOG_INFO("Data received - reading data()");
	        
	    } 
		
}

And well i am stuck here, just getting 253 on putty, as if the register is ignored somehow =\

RE: Serial display of data using TWI

Jared — Wed, 20 May 2020 09:56:01 GMT

Hi.

Have you made sure that you're using the recommended Putty settings as described in the TWI examples? Is the NRF LOG output displayed? Have you made sure that the application haven't asserted?

regards

Jared