This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TXB0304 between a PIC24FJ128GA202 and a 4 GB, Panasonic, RP-SMKC04, SDHC - SPI

Other Parts Discussed in Thread: TXB0304

I placed a TX0b304 between a PIC24FJ128GA202 and a 4 GB, Panasonic, RP-SMKC04, SDHC and communicate via SPI.

I was not reading the correct value after a write.  After some reading I decided added 10 kohm pull-up resisters to the PIC side of the level converter.

Did not change the results.

Read the txb0304 spec again and read that if I were to add pull-up resistors then they should be greater than 20 kohm.

Q1:  Do I need pull-up resistors for this application?  I don't know if the SDHC card is open drain, collector or what not.

Q2:  If yes then would which side of the level converter would I need to place them?  PIC side, MSDC side, both, neither?

Thank you,
Craig

  • Craig,


    I've moved this post to the Voltage Translation/Level Shifters Forum, where the TXB0304 is supported.


    joe wu
  • Hello Craig,

    To be safe you should pull-up the CS line. For the CS the pull-up would be on PIC side of the translator. As for the other lines, there seems to be conflicting information as to whether or not pull-ups are absolutely necessary. I would say that they couldn't hurt. A resistor greater than 20k should be fine in this application.