Board Lock-Up on Watchdog Reset

[PaulDeMetrotion]

Developed a custom board based on the i.MX6Q. We are using the internal watchdog timer and the watchdog reset works fine when we perform a reboot command.The WDOG_B signal is being routed to the POR signal of the i.MX6 device.

We are running a watchdog timer test and the board will periodically lock up after the watchdog expires and generates an internal reset signal. It appears to be locking up early in u-boot. 

The behavior seems very erratic and is affected by odd functions like:

  1. DHCP in progress or not

  2. Length of timeout - 5 seconds will not lock up while 60 seconds will

I know this is very vague but looking for any ideas at this point.

[PaulDeMetrotion]

Thanks Igor. I removed the PMIC device from our device tree essentially disabling the programmability of the PMIC (we use pre-configured devices). Early testing show this may have resolved the problem. We do not have the PWRON signal connected to the PMIC PWRON pin. This may be the issue. Updates to follow...

[igorpadykov]

Hi Paul

if this is in uboot one can try to debug it and trace where it stuck

(comparing with working case). Some board peripheral chips may be not in

default state (as in power-up), so recommended solution is to reset whole

board with pmic (using PWRON) as in Sabre SD schematic spf-27392 p.21 U507

Schematics (1)
Design files, including hardware schematics, Gerbers, and OrCAD files
SABRE Platform for Smart Devices | NXP 

Best regards
igor
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