SD card DET pin

Question

Hi everyone,

I'm working on a new design based on the PicoZed FMC Carrier Card V2. I'm considering using a micro SD card connector without insert card detection signal (DET).

In the schematic of the PicoZed FMC Carrier Card V2 is called SD_CD.

When the SD card detection is activated, the pins G3 and G4 are open and the SD_CD signal is high due to the pull-up resistor R68. If the SD card isn't inserted then the pins G3 and G4 are close and the SD_CD signal is GND.

What do I have to consider in the design?

Do I have to place a pull-up resistor to simulate that the SD card is always inserted?

Obviously, I only could insert the SD card when the system is power off. But It's not always going te be inserted an SD card.

Best regards.

drozwood90 · Accepted Answer

Hi there, I checked with a few colleagues. From what our experience has shown, you should be able to control that line internal to the Zynq. As I understand it, we actually used to do this pre-2015.2. From what was explained to me, you actually can control the CD and WP lines without the need for external straps. My suggestion is to put pads for the lines that you can. You can always not-populate them for your design and use the internal mechanisms. --Dan