• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 47 subscribers
  • Views 359 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADC12DJ3200EVM: OVR_T1 is only triggering when OVR_T0 is triggered despite being programmed for a lower threshold

Dan Skehan7
Intellectual 560 points
Part Number: ADC12DJ3200EVM

Hi,

I have programmed an ADC EVM using the TI ADC GUI to the following values:

0x211 OVR_T0 0xF2 (-0.5dB)

0x212 OVR_T1 0x1A (-19.87dB)

0x213 OVR_CFG 0xF (enable ovr, 111 samp period)

When I raise power levels in 0.1dB increments I do not see the OVR_T1 threshold trip until the OVR_T0 threshold is reached. At which point both are triggered. I can see this both with sticky bits from my firmware connected to the board and the orange LEDs that light up on the ADC EVM.

I have tried this with several OVR_T1 with the same results. 

What could be causing this?

Thanks in advance,

Dan

  • 0
    TI__Genius 12780 points

    Hi Dan,

    One of our device experts is looking into your question, and will be back with you soon.

    Best Regards,

    Dan

  • 0 in reply to dBrock
    TI__Mastermind 38690 points

    Hi Dan,

    Sorry for the delay....we didn’t see this in simulation. There is no requirement for OVR_T1 to be higher or lower than OVR_T0. They are just two independent thresholds.

    We had some follow on questions/comments about this. Can you please address?

     

    • Have you read back the OVR_T0 and OVR_T1 registers to make sure they are being written correctly?

     

    • Can you swap the OVR_T0 and OVR_T1 values and see what happens? Do both over-range outputs trigger at -19dB or -0.5dB?

     

    • There are four over-range outputs in total (ORA0, ORA1, ORB0, ORBA).  The exact over-range outputs were never mentioned any by name above, could you please make it clear which over-range outputs are being looked at?.

     

    • Are you using this in DES mode? If so, in DES mode, the ORA0 and ORB0 will both trip at the same time based on OVR_T0. ORA1 and ORB1 will both trip at the same time based on OVR_T1.

     

    • Also please make sure the special threshold mode isn’t enabled (register 0x213, bit 4).

    Hope this helps and let us know what you find.

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    Intellectual 560 points

    Hi Rob,

    Thank you for your reply.

    I went through each item you listed and as it turns out we had the OVRB0 being routed instead of OVRA1.

    Thanks for steering me in that direction to look for that.

    -Dan

  • 0 in reply to Dan Skehan7
    TI__Mastermind 38690 points

    You are very welcome Dan! Glad you found the issue.

    Regards,

    Rob