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TMS570LC4357: on-board temperature sensors

Part Number: TMS570LC4357

Hello,
I am using TMS570LC43 trying to read the internal temperature sensors for now I am testing T1 which is connected to AD1IN[31]

my first question, can I use this temperature sensor to read the room temperature or its a kind of indication for the internal processor temperature which will be different than the room temperature 

second question, regarding the calibration values of the sensor according to reference manual table 7-8 ,

-- ADC value Temperature 
lowest calibration 1957 303
midpoint 1543 233
highest calibration 2528 398

how are the values of the midpoint lower than the lowest calibration !!! this is very strange for me
according to this table the linear equation of the temperature is (Temp = 0.169082 X ADC_Value -27.8937
so for example I am reading 3051 at the room temperature and this means 214.9758454 which doesn't make any sense for me 

  • Hello,
    On-die temperature sensors are not suitable for room temperature sensing! They are for monitoring the junction temperature.

    See this file for example how to use on-die sensors: www.ti.com/.../spna216.pdf

    Best regards,
    Miro
  • The temperatures: 303 equals 30C, 233 equals -40C and 398 equals 125C (the temperatures are in degrees Kelvin). So you see they are not in order of increasing temperatures, which is why they may seem strange.
  • Hi Sunil,
    Thanks for your reply
    yes I know that they are in kelvin but still the midpoint temperature is lower than the lowest temperature?
    and if I am getting 2930 on the ADC side it means 467.5169082 Kelvin or 194.5169082 C does it make sense to have this 190C temperature for the processor junction when the room temperature is around 25
    I am just asking as I don't have that sense about the internal temperatures of the processors