Sorry, you need to enable JavaScript to visit this website.

SD card classes

6 posts / 0 new
SD card classes


i can't really find information on what classes of the sd-card are supported by the zedboard. I know that their is an SD-card class 4 with de zedboard. But are the SD-card like UHS-I supported?


According to the Zynq TRM,

According to the Zynq TRM, "It does support SD high-speed (SDHS) and SD High Capacity (SDHC) card
standards. The user should be familiar with the SD2.0/SDIO 2.0 specifications."
Since UHS-I cards are specified in SD Version 3.01, I would say they are not supported. However, you could open a support case with Xilinx for clarification.


Hi mqoubert, did you finally tried the UHS-I SD card? Do you know a compatible good alternative form the performance point of view?

No, if someone did, let me

No, if someone did, let me know! :)

SDXC Support

Along the same lines SDHC tops out at 32GB, but, as usual, I want more!!!

The post at talks about someone using a 64GB SDXC card.

Since SDXC is from the SD 3.0 spec, there is a good chance that UHS-1 will work, but higher levels won't as there are some bits to check and they come from the 4.0 standard, which SDHC readers don't check.

RE: SD card classes

Hi mgoubert and hrebec,

I was looking at a similar issue the other day. I am not all that familiar with any of these SD specifications but I did come across this on a Panasonic website:

According to that page, UHS-I supports three modes DDR50, SDR50, and SDR104 with each one having higher clock rates than the 50MHz which we currently use with SD cards on ZedBoard.

The reason I bring this up is that we have a TXS02612RTWR level translator at location IC8 to translate the Zynq 1.8V IO bank to the 3.3V level used by the SD card slot. According to the datasheet for the TI translator device, clock frequency translation tops out at 60MHz according to their Timing Requirements table.

So even if the Zynq SDIO controller supported the UHS-I cards you would likely need a different level translator or a direct connection between Zynq and the SD card slot to achieve the higher throughput that you get with UHS-I cards. This is something to keep in mind as well while you are experimenting.