EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Apix on September 06, 2022, 07:41:52 am
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Hi there :)
I'm working on a board that I developed by myself. I've a problem with some integrated EMI Filters. I have an STM32 MCU connected to a micro sd. I've placed some emi filters between the STM32 and the uSD card connector.
In the first relese of the board I've used some ST EMIF06 and everything was ok. Due to IC shortage I had to change the EMI Filters and I'm currently using some Nexperia IP4254CZ8-4.
The problem is that I'm not able to mount the uSD card from the STM32. I've changed my FW to just use a single data signal instead of the whole 4 bits bus and what I've seen is that placing a flying wire on the bus lines let the uSD Card be mounted.
I'm not able to understand if it's a capacitance problem or something else. It seems also that putting a little capacitance to ground doesn't affect anything. Putting the same capacitance to vcc everything works fine.
I've also attached part of the schematic.
What you think it might be which causes this failure?
Thank you very much for your time!