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CCS/PGA970: PGA970 Internal Temperature Sensor

user4962020
Prodigy 40 points
Part Number: PGA970

Tool/software: Code Composer Studio

hello!

i want to use the PGA970 Internal Temperature Sensor  ,  in pga970's  datasheet page 8 and page 25:  "in order to improve the accuracy of the temperature sensor in the 25º to 125ºC range, every device has several
unique temperature code values pre-written to the FRAM to specify more-accurate gain and offset values. A signed, 32-bit value for the 25ºC temperature point of this device is located at FRAM address 0x3FFC, and a 32-bit 125ºC temperature point is located at FRAM address 0x3FF4 ."

but how to read the value at address 0x3FF4 and 0x3FFC?

I looked up the information and FRAM's address did not seem to contain it?

Please reply as soon as possible how I use the internal temperature sensor for temperature measurement.

In addition, I put the PGA970EVM board into the high and low temperature test box, and then test the PTAT value of the internal temperature sensor ADC3 at different temperatures.

At -22℃, PTAT = 334397, at - 12℃, PTAT = 345702, and at - 2 ℃, PTAT = 357335.... This can roughly calculate the temperature gain of 1200LSB/℃  below 0℃. But on page 8 of the data sheet of PGA970, it says 6950.8LSB/ ℃, so why not be consistent?

thanks!

  • 0
    TI__Mastermind 31655 points
    Hello,

    Are you using the PGA970EVM for now? You can perform a dump of the FRAM contents using the GUI which should include those temperature data registers.

    As far as the difference in the gain is concerned, the internal temperature sensor specifications are typical values, and could actually vary quite a lot from device to device. This is why a calibration is important to get consistent results.

    Regards,
  • 0 in reply to Scott Cummins
    Prodigy 40 points

    hi Scott, thanks for you reply.

    yes, i am using the PGA970EVM.   But I can't find how to read the contents of 0X3FF4 and 0X3FFC addresses in FRAM on the GUI .

    Can you specify it?  or give out a CCS code?

    If the internal temperature sensor gain of each PGA970 is so different below 25℃, how can I use it in batches?

    Regards,

  • 0 in reply to user4962020
    TI__Mastermind 31655 points
    Hello,

    In order to read the FRAM, you must go to the "FRAM & DEVRAM" page (just above the low level configuration page you have highlighted). You can dump the FRAM contents to a file and read the values this way.

    Regards,