The sd_temp_get() function

[Mahendra Tailor]

Hi

I am using v6.0.0 softdevice S110 and SDK 5.1.0

In nrf_soc.h the function sd_temp_get() is defined. The comments there say ..

"p_temp Result of temperature measurement. Die temperature in 0.25 degrees celsius"

I have both an early variant of the nrf51 and the XLR2 in our modules. Both modules are about 10 centimeters apart and I would say they are sitting in the same temperature environment, hence I would say with certainty they are at the same temperature.

On the early variant of the chip sd_temp_get() is returning a value of 138 On the XLR2 it is returning 113

If I go according to " Die temperature in 0.25 degrees celsius" then it implies I need to divide by 4 to get the actual temperature, hence ..

138/4 = 34.5 113/4 = 28.25

I have 2 temperature sensors within a meter of the devices in my office. One is showing me about 22 and the other 23.

I am confused.

Look forward to hearing from someone.

Kind regards and thank you in advance Mahendra

[Mahendra Tailor]

Good point. In my case in both instances the radio is not operating and the only peripheral that is switched on is the uart which means the current consumption is about 1mA

I am not a hardware engineer.

Given that 1mA is being consumed at 3.3V that corresponds to 3.3milliwatts of power. Is that enough to heat it up?

However, just in case I will switch off the unit overnight and try it first thing tomorrow morning by taking the measurement within a few seconds of power on.

Our module has an AT command interface and I have added an AT command to return that temperature.

Had a look at the datasheet and you are right, it is accurate to +/- 4.

Thank you for providing the feedback.