The SMARC pin P128 should be controlled through an Open Drain output on the carrier board. In our EVK, we have implemented a switch that causes the SOM to behave as follows:
SOM Power ON – Press and release once
SOM Power OFF – Long press (more than 5 seconds)
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G33M product information in the below link,