Hello,
We are using TM4C129ENCZAD in a released product for a couple of years now, and the released product uses hibernation mode. Lately, we have seen a few devices coming off of our manufacturing line that will not wake up from hibernation mode. I can provide mode details if needed but here is a short summary of the issue we are seeing:
- The device powers up and enters hibernation mode with hibernation wake up set to HIBERNATE_WAKE_PIN
- We verify HIB pin is asserted in this state
- We press a button that asserts WAKE pin
- We see HIB pin gets de-asserted which enables our VDD regulator
- ~1 ms after HIB pin gets de-asserted, VDD is stable at ~3.3V
- At this point, it seems like our code does not get executed
The first couple of lines of our code enable a GPIO output, set the output to 1 and wait for ~500 ms before clearing the GPIO output (the GPIO output drive an LED to indicate the device is "alive"). In step 1, we can see this happening. But after step 5, we do not see this happen. Its almost like the TIVA part itself is not coming out of reset after step 5. Has anyone seen anything like this? Is there something else we should check?
Note that this has now happened on 4 devices out of hundreds so it does not happen often.
Any help or guidance would be appreciated.
Thanks,
Mitch