Use temperature in Eddystone (TLM)

RE: Use temperature in Eddystone (TLM)

Nitram — Fri, 19 Aug 2016 09:05:29 GMT

Thanks, that is what i have looking for. Now, I want to send the temperature. Therefore, I have to make 8.8 fixed-point notation (courses.cit.cornell.edu/.../). I have try it, but it does not work. I have program following code:

int32_t	temp;
float	temp_f;
int 	temp_i;

sd_temp_get(&temp);			//get temperature

temp_f =  (((float) temp) / 4);		//temperature from 0.25 degrees Celsius to 1 degrees Celsius

temp_i = ((int)((temp_f)*256.0)); 	//Convert float to fix

Maybe you could help me a second time. Thanks.

RE: Use temperature in Eddystone (TLM)

Susheel Nuguru — Wed, 17 Aug 2016 07:53:42 GMT

sorry forgot about that, my bad. This module is restricted so you cannot directly access it when softdevice is enabled. You have to use sd_temp_get which is a softdevice API and you can find it in nrf_soc.h.

/**@brief Get the temperature measured on the chip
 * 
 * This function will block until the temperature measurement is done.
 * It takes around 50us from call to return.
 *
 * @param[out] p_temp Result of temperature measurement. Die temperature in 0.25 degrees celsius.
 *
 * @retval ::NRF_SUCCESS A temperature measurement was done, and the temperature was written to temp
 */
SVCALL(SD_TEMP_GET, uint32_t, sd_temp_get(int32_t * p_temp));

The value returned by this function is the direct value read from the chip NRF_TEMP->TEMP register. You can use this API even when you have RC clock with calibration on triggered by temp changes.

RE: Use temperature in Eddystone (TLM)

Nitram — Wed, 17 Aug 2016 07:17:21 GMT

Thanks, but is it possible to combine the temperature measurement with the oscillator?

nrf_clock_lf_cfg_t clock_lf_cfg = 
{
    .source = NRF_CLOCK_LF_SRC_RC,
    .rc_ctiv = 16, // Interval in 0.25 s, 16 * 0.25 = 4 sec
    .rc_temp_ctiv = 2, // Check temperature every .rc_ctiv, but calibrate every .rc_temp_ctiv 
    .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_250_PPM,
};

RE: Use temperature in Eddystone (TLM)

Susheel Nuguru — Wed, 17 Aug 2016 07:03:56 GMT

please look into the example of temperature sensor in

nRF5_SDK_v11_0_0 folder>\examples\peripheral\temperature\main.c\

to understand how you can use the API in nrf_temp.h