topic Re: MPC5775B internal temperature sensing in MPC5xxx

MPC5775B internal temperature sensing

bharathn3402 — Tue, 24 Sep 2024 16:13:47 GMT

Hi,
I am trying to calculate the temperature using the MCU's internal temperature sensors. I read the ADC voltage values for the local bandgap, TempSense-1, and TempSense-2, and used the formula provided in the reference manual. I also read the calibration values from the UTEST memory:
- Sensor 0 Cal A: 237
- Sensor 0 Cal B: 54
- Sensor 1 Cal A: 127
- Sensor 1 Cal B: 1

Based on these values, I'm calculating a temperature. However, when compared with a temperature monitoring camera, the readings show a 5-10°C difference (lower in my calculation). Additionally, the MCU is resetting when the temperature reaches 180°C based on my calculations, but the reference manual indicates that the MCU should reset at 150°C.

Re: MPC5775B internal temperature sensing

petervlna — Thu, 26 Sep 2024 07:39:00 GMT

Hello,

The sensors measure the temperature inside the silicon. And you measure it on the surface.

With 150C are you referring to Junction operating temperature range?

Where do you read that at 150C you will get reset?

Best regards,

Peter

Re: MPC5775B internal temperature sensing

bharathn3402 — Thu, 26 Sep 2024 09:55:23 GMT

Hi,

I measured the internal temperature sensor value using the ADC, which provides the junction temperature. The MCU's operating temperature range is from -40°C to 150°C, and the reset condition is mentioned in the PMC_REE_TD register.

I measured the MCU's internal sensor ADC values and performed calculations as outlined in the reference manual. I validated this with a thermal camera by measuring the MCU surface temperature. When the surface temperature reached 180°C, the MCU reset, and once it cooled down, it returned to normal operation.

Do you have any idea about the ADC values generated at certain temperatures for a 14-bit ADC? Also, I need more information regarding the ADC reference voltages.

Re: MPC5775B internal temperature sensing

petervlna — Tue, 01 Oct 2024 07:04:13 GMT

Hello,

Do you have any idea about the ADC values generated at certain temperatures for a 14-bit ADC?

No, as each chip has unique calibration values. There is no point to have such

Also, I need more information regarding the ADC reference voltages.

Not sure what you need. All available specifications are in datasheet.

Best regards,

Peter

Re: MPC5775B internal temperature sensing

bharathn3402 — Mon, 25 Nov 2024 14:41:24 GMT

Hai @petervlna , Can i have an example code for MPC5775B ADC Initialization, Reading for SDK Peripheral Abstraction Layer for Analog to Digital Converter (ADC PAL)
Repository: SDK_S32_PA_15 .