SDCARD_WP Polarity

Hello,

I am going to use a MicroSD card on my carrier card without a write protect switch, so I want to ensure I wire it correctly. This is my question.

The documentation seems to indicate that SDCARD_WP is active high, not active low (by the naming convention without a “#”). If I want to write protect my SD card, should SDCARD_WP pulled high or low. I am thinking it should be pulled low to write protect, since there is a pullup on the TX1 module.

Thanks.

It’s low enable, there should be a “#” to it, will fix in future version, thanks.

Correct:

Hi johnq,

After internal checking, the SDCARD_WP is high enable, when a locked card inserts, the SDCARD_WP will keep high.

Hello,

I am just looking at the response, and it looks like originally you said it’s low enable, then changed to high enable.

Could you please confirm if the SDCARD_WP needs to be high or low to write protect the card.

Interestingly, the OEM Product Design Guide indicates there is a pullup on the Jetson TX1, meaning if I don’t use it and leave it floating on my carrier board (and the signal is active high), I wouldn’t be able to write the card unless I have a pull down on my carrier card always installed.

Thanks again for the help.

Yes, there is internal pull up on this pin, and it needs to be pulled low if want to write card.