When the battery is low, the program freezes and the watchdog cannot be reset. J-link can't read the device

RE: When the battery is low, the program freezes and the watchdog cannot be reset. J-link can't read the device

JONATHAN LL — Fri, 16 Aug 2024 07:18:17 GMT

Hi Sok,

Can you measure the voltage on the VDD pin close to the SoC, so that you can see what is happening at the chip. Best is to use a scope and capture the issue that is happening.

Also can you disable pin reset and see if the issue still happens.

And what you explain sounds like a BOR\POR reset loop, but this can only happen if the voltage is under brown out levels, so under 1.8V at least. And if the battery has a high seires resistance and is close to empty or bad in any way.

Regards,
Jonathan

RE: When the battery is low, the program freezes and the watchdog cannot be reset. J-link can't read the device

Turbo J — Fri, 16 Aug 2024 07:13:51 GMT

Redesign most likely.

In my opinion you need the protection/battery management circuitry to open the discharge FET below roughly 3.3V for normal LiPo chemistry. There is close to zero runtime left below that and it murders the battery. The internal resistance raises sharply, too.

Brownout behavior can vary wildly between µC samples. And its possible that a device self-destructs in a brownout condition by erasing/overwriting flash memory.