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TM4C129 Hibernation Issue

Donald Kotas
Prodigy 20 points

We've recently designed a new board using the TM4C129 processor and are having a hard time getting the micro to stay in hibernation.  We have a lithium coin cell connected to VBAT and a 3.3V switched supply connected to VDD.  We have a 1Meg pullup resistor connected to the lithium voltage on the WAKE pin.  When we issue the hibernation command, the HIB~ signal activates for a little over 3 milliseconds then goes high.  Startup code tells us that hibernation mode is no longer active and that a POR reset has occurred.  Any thoughts as to why this is happening?  One interesting note is that if I leave the VDD power on, the unit will go into hibernation and stay there.    

  • 0
    TI__Guru 59540 points
    Hello Donald,

    This sounds much like another issue I had seen reported recently. During this investigation, it was discovered that a call of HibernateWakeSet API was also setting the mode to VDD3ON even though it was not desired. This caused the device to enter Hibernate for a very short duration as you describe then exit. It was solved by placing a call to HibernateGPIORetentionDisable after the hibernate enable to insure it was in the VDD3OFF mode and made the successful switch to hibernate with battery powered backup.

    Can you give this a try and let me know if it resolves your issue?
  • 0 in reply to Chuck Davenport
    Prodigy 20 points
    Chuck,

    Thanks for your help. Your suggestion solved my problem and the micro now goes into hibernation mode and stays there.

    Thanks again,
    Don