Hello Dear Community Members,

I am trying to develop a microSD card module. My microSD card module is working at 3.3V and my microcontroller is operating at 1.8V. I have therefore used TXB0104 voltage level shifter to interface.

Attached below is my PCB schematic. The legend is as below: BOOST_OUT= 3.3V BUCK_OUT= 1.8V

I am not quite sure if my circuit is entirely correct. Some specific doubts that I have are:

I am using microSD card in SPI mode. Are my socket pin interpretations correct? I have used Sandisk datasheet as my reference (Page 10 of https://www.alliedelec.com/m/d/04db416b291011446889dbd6129e2644.pdf)

Should I pull up all my DAT0:3 pins to BOOST_OUT (3.3V)? I know that the microSD card datasheet says that this is applicable for SD Mode, but am confused if this is applicable to SPI also.

Should I pull up Chip Select (CS) to Boost_Out. In doing so, what will happen? I want to control the ON and OFF of the SD Card module in my application. I therefore have pulled my OE pin of TXB0104 to micro controller. Do I have to do the same for CS also or is only one of them necessary?

Please point out any other corrections also, if you find them! Sorry for blasting off with so many doubts, hope you will be able to help :)

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