SDCARD_WP Polarity

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX1
1

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.

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2

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.

3

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.

4

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

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