topic Re: Setting ADC to Temperature Sensor in S32 SDK

Setting ADC to Temperature Sensor

gearhead1107 — Wed, 16 Aug 2017 22:13:07 GMT

I'm trying to set my ADC component to use the S32's internal temperature sensor, however when setting the Input Channel, there's only options for channel AD0 - AD31, however the reference manual (ch38, Chip-specific ADC information) mentions that Vref and temp sensor should also be available. I assume I need to just manually set the ADC to the corresponding value, but is there a way to do it in Processor Expert?

Re: Setting ADC to Temperature Sensor

gearhead1107 — Thu, 17 Aug 2017 14:18:40 GMT

Making progress on this - figured out that you just need to set ADC0 to channel AD26 for temp input. The other options can be found in S32K144_features.h

#define ADC_INPUTCHAN_TEMP ADC_INPUTCHAN_AD26
#define ADC_INPUTCHAN_BANDGAP ADC_INPUTCHAN_AD27
#define ADC_INPUTCHAN_VREFSH ADC_INPUTCHAN_AD29
#define ADC_INPUTCHAN_VREFSL ADC_INPUTCHAN_AD30
#define ADC_INPUTCHAN_DISABLED ADC_INPUTCHAN_AD31

I'm still not 100% sure how to scale the ADC reading to temperature - so if someone could help there it would be great!

Re: Setting ADC to Temperature Sensor

ovidiualexandru — Mon, 21 Aug 2017 09:32:51 GMT

Hi gearhead1107‌,

The temperature sensor of the K144 is not well documented. On newer chip revisions (maskset 0N57U) it's possible that it's not even included on-chip.

In the Reference Manual, on page 1921, "A.39.2 ADC module changes" there is a mention that the Temperature Sensor bullet was removed.

Unfortunately I cannot find any more information about this feature, as it seems it was a preliminary feature on early hardware revisions.

Best regards,

Ovidiu