I am trying to develop a microSD card module myself. 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?
Too many doubts, sorry for blasting them! I will be grateful for your help and support :)