FEZ Panda II MicroSD Card Detect pin

The FEZ_Panda_II_UserManual says that the SDMicro card detect is accessible, but does not say which IO pin it is connected to.

Based on the sample:

Auto-Mounting SD Cards, option 2.

Does anybody know which pin to use on the Panda II?

This is the default in the example
// Set the SD detect pin
sdDetectPin = new InputPort(EMX.Pin.IO36, false, Port.ResistorMode.PullUp);

but it states that:
Make sure to change the I/O pin number to whatever I/O pin is actually connected to the detect pin.

Looking at the schematic Card Detect on the MicroSD is pin 2 which is connected to IO50.
Should the IO pin for auto card detect to use for the Panda II be IO50?


Schematics is on the Panda page on catalog


IO50 seems to be “SD_DAT3” therefore it might not be the card detection PIN.
I would bet on “CDN” / IO43 / Pin 9, but you have to check I guess with a multimeter :wink: (I would do it but my pandaII is at home).

This connector has a dedicated detect pin, you do not need to use DAT3

According to this pdf:


pin 2 on theMicroSD is CD/DAT3: Card Detect/ Data Line [Bit 3]

In that this is a dual use line, I am trying to find out if this what would actually be understood by the driver as Card Detect as it changes to being the DAT3 pin after the SET_BUS_WIDTH command is issued by the driver.

Which is the dedicated detect pin - is it pin 9 - CDN?
Which pin does not seem to be detailed on any documentation…nor is what CDN stands for.

I guess it is documented in MicroSD documentation.Try to look there for CDN abbreviation.

Yes, CardDetectNegative.

After reading this thread, I wanted to make sure I got it right.

The help file talks about the DAT3 SD line as a detection means. According to the above exchange, the connector used in the Panda II has a dedicated pin for card detection. With that said, I have three questions:

  1. Is the help incorrect for the specific case of the Panda II with the connector it uses? That is, calling DetectSDCard() in this platform will base its result on IO43 which is connected to the CDN, and not on IO50?

  2. The help mentions that DAT3/CS is not supported by all platforms as a detection means. Is CDN more pervasive or perhaps mandated by the SD spec?

Thanks for any input on this.

You should use the card detect pin. DAT3 is a non favorable option but had to use it because the old card connector didn’t have card detect on it.

The API has an specifically named SDDetect on the list of Digital IO names so it is easy to find.

I just ordered some USBizi100 Chipset for a project which will have an SD card. The Panda II and FezMini both use the USBizi100 and both have an SD card. So I thought they would both have same pinout for micro SD card - but that is not the case.

Please confirm

1.) On the schematic for the Panda II, IO43 is connected to the card detection switch on the Micro SD connector (true/false)?

2.) On the schematic for the FezMini, IO43 is NOT connected to the microSD card connector AT all (True/False)? Instead the Mode pin is connected to SD expansion header - is this pin used for Card Detect?

Finally, when I design with the USBizi100 chipset, which pin should I use for Card Detect ??
Put another way, does the USBizi100 come with Panda II firmware, FEZmini firmware or is it blank?

And lastly, it appears the Fez Mini is being phased out based on the fact that the Fez Mini Eval kit is no longer being offered. If true, those this mean I should pick Fez Panda II firmware and thus use Fez Panda II schematic for reference design?


Replying to old threads is very bad to other readers. Can you please start new thread with your question?

Hi Gus,
Sorry about continuing in a previous thread. I thought it was relevant as someone else had a similar problem. I have posted a reply to Rajesh´s suggestion still in same thread.

Can you please help to create a new thread and move my posts to the new thread ? I am quite new in using forums and not sure how to do the above.

Thread name : FEZ Panda 2 MicroSD reports unformatted status

This post can also be removed if not to be public nuisance!
Thanks for understanding

Hi Gus
Sorry about replying to an old thread. After I did this, I noticed how confusing it was and posted a new thread which references this thread.

See http://www.tinyclr.com/forum/2/4628/ for my new question.