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Original question:

CCS/TMS570LS0432: Capturing two frequencies with the HET

CCS/TMS570LS0432: Self Test Mode for HET-Pins?

Christian Schau
Intellectual 260 points
Part Number: TMS570LS0432

Tool/software: Code Composer Studio

Hello,

I was wondering if there is something like the Self-Test-Mode of the ADC-Pins ofr the HET-Pins to recognize if a shortcut or open-wire error occured.

In my current program for example, the last read period and duty stay in the memory, when i disconnect the wire from the HET-Pin.

Kind Regards,

Christian

  • 0
    TI__Mastermind 21425 points
    Hello Christian,
    There is no such mode but you can still make some tests.
    For example in GIO mode you can set pin as output and set it to high/low. Then you can read back the input buffer to see whether it matches.
    N2HET[0], N2HET[2], N2HET[4], N2HET[6], N2HET[8], N2HET[10], N2HET[12], N2HET[14], N2HET[16], N2HET[18], N2HET[22] and N2HET[24] pins are zero dominant (if two pins are shorted, one is driven high while the other is driven low, the result will be a logic low). This also can be used for testing. For example if one pin is set to high and its adjacent pin is set to low and you read low for both, then pins are shortened.

    Best regards,
    Miro
  • 0 in reply to Miro
    Intellectual 260 points
    Hey again,
    I actually looking for shortcuts to ground and 5V (and for open circuit).
    So you are suggesting i should set the pin to output and high. Then change it to input and read it. if it is low, there is a shortcut to ground? and vice versa?
    For me this won't work: what if my signal is actually low at the point of reading the pin?

    I assume the HET just continously counts up if there is a short cut to high or low potential, because there is no edge to detect. If so does the capture return the old measurement of duty and period?
    Furthermore I assume at some point there is an overflow which could be read. But after what time does the counter overflow?
  • 0 in reply to Christian Schau
    TI__Mastermind 21425 points

    Hello Christian,
    You can use Automatic Read Clear Feature ( Section 17.2.4.3 of device TRM ). This is bit26 of PCNT Control Field. This feature will automatically clear the data field immediately after the data field is read by the external host. In that way when signal is disconnected values will be 0.

    Best regards,
    Miro

  • 0 in reply to Miro
    TI__Mastermind 21425 points
    Hello Christian,
    I hope you found a way to solve this. I m going to close this thread for now. You can always reopen with writing bellow or you can open new thread.

    Best regards,
    Miro