AB1805 watchdog and the B Series

[gusgonnet]

Hi,

I am helping design a board using a B Series 402.

When adding the watchdog, we chose to follow the AN023 Watchdog Timers and the AB1805.

In it, the AB1805 is able to completely power cycle the MCU on a boron, with the EN pin:

Now, if one wanted to do the same thing in a B series 402, where I cannot find the EN pin, what is the recommended way?
(perhaps @rickkas7 can comment here, please, and a million thanks!)

Thank you!
Gustavo.

[rickkas7]

The EN pin on the Boron looks like this:

Since the B series SoM doesn’t have a PMIC or voltage regulator on it, there is no built-in EN pin. If you are using the bq24195 on your B series SoM board, the EN pin can connect to a load switch (XC8107, for example). It goes between the SW output of the bq24195 and should turn off both VSYS (VCC or 3V8 on the B Series SoM) and the 3.3V regulator (to 3V3).