1.8V (PWR_1V8CI_MOCI) shut down during reset on Verdin iMX8MP

When pressing the reset button (CTRL_RESET_MICO#) the 1.8V output on Pin214 (PWR_1V8CI_MOCI) cycles (shut down and then swich on). On our own carrier board we have the problem that the 1.8V does not come up after pressing the reset button. We use the PWR_1V8_MOCI for supplying components on our carrier board (e.g. the second ethernet phy and an additonal eMMC). The problem may have its cause as both ethernet phy and eMMC have two voltage rails and the other one isn’t switched down during reset. During power on we have no problems.
Why is the voltage output switched off during reset and can we prevent the verdin board from doing this?

1 Like

Hello @rosenheim ,
Is it possible for you to share the schematics of your board? It might be a backfeeding issue.
It is advisable to send us your schematics for us to perform a free 30min check in order to avoid issues like the one you are experiencing.

Best regards,

This is an expected behavior, The PWR_1V8_MOCI rail supplied by onboard PMIC buck converter and CTRL_RESET_MICO# signals resets the PMIC as well. Please check the Verdin Carrier Board Design Guide for details:

Unfortunately it’s not possible to prevent the Verdin module from doing this. You have to modify your carrier board design. Please also note that the PWR_1V8_MOCI rails can supply max 250mA

Hallo Alex,

thank’s fort he reply. Can you please remove our schematic from the forum’s page, it is confidential.


@rosenheim ,

Done :slight_smile: