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STM32MP157 and LPDDR3 unused MPU pin consideration

Badzonor
Associate III

Hello,

I designed custom board with STM32MP157 and LPDDR3 memory. Due to PCB manufacture restrictions I needed to connect to ground unused signal called DDR_ATO. I want to know if this is a problem, because if it is the case I can just remove 1 ball from the IC and solder it like that, but maybe it is not necessary?

 

Thank you, Dominik.

1 ACCEPTED SOLUTION

Accepted Solutions
PatrickF
ST Employee

HI @Badzonor 

We did not recommend to connect VSS to DDR_ATO ball.

DDR_ATO pin should be left open or connected to a test point.

Nevertheless, as a temporary workaround to start playing with your board, and until PCB is fixed, you could probably do it as it is mention that the pin will output '0' when not enabled.

PatrickF_0-1719840623860.png

 

Regards

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

View solution in original post

1 REPLY 1
PatrickF
ST Employee

HI @Badzonor 

We did not recommend to connect VSS to DDR_ATO ball.

DDR_ATO pin should be left open or connected to a test point.

Nevertheless, as a temporary workaround to start playing with your board, and until PCB is fixed, you could probably do it as it is mention that the pin will output '0' when not enabled.

PatrickF_0-1719840623860.png

 

Regards

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.