WP85 i2c transactions fail after trying to probe low power MCU


#1

Hey all,

This is an issue we’ve been discussing on the MangOH forum here: https://forum.mangoh.io/t/gpio-stops-working-after-several-hours

In essence, the WP85 occasionally fails to probe the low power MCU (referred to as swimcu on the i2c bus @ 0x003a). To my knowledge, this chip is internal to the WP85 and is used for waking up from ultra low power mode using a few special GPIO pins. Losing the GPIO pins hosted on the MCU is not ideal, but the real concern here is that we lose all of our mission critical i2c peripherals (accelerometer, temperature/humidity/pressure).

In terms of hardware, we’re using a board based on the MangOH Red with a few key differences as outlined in the forum post above.

Let’s try and keep the discussion on the MangOH forum if possible. Mostly just looking to reach the widest audience possible (cross posted on the Legato forum as well) to see if anyone else has experienced this.

Cheers!


#2

Hey all,

Wanted to take a moment and report where we are at with this issue. After weeks of debugging, it seems this issue is a result of something in our hardware.

Apologies for the confusion,
Cheers!