mm9z1-638: PCR_SR register question

[gumu]

Dear Sir:

We have a question about the booting reason after coming up from the stop mode. The value of the reset reason register is 0x0908, according to the PCR_SR register description, showing the HVRF and WLPMF waking up. While we can understand the WLPMF wake-up reason, why is the HVRF wake-up reason set? Is this normal?

[gumu]

Hi @Q_man ,

Sometimes, we receive a reset reason of 0x100. Please refer to my other post for the description.

MM9z1-638:no wakeup reason - NXP Community

[Q_man]

Hi Gumu,

The 0x0908 makes sense and is expected!
The PCR register latches all conditions since last clearing of bits:

- device did wakeup based on PTB4 (WLPMF and WUPTB4F)

- device saw low voltage condition on VDDH (voltage of D2D Interface). VDDH is turned off during STOP mode.

W.