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Micro SD card problem

Added by joostn over 10 years ago

Hi,

I've soldered my brand new rev5 board and everything is working except for the micro sd card. I've used the Molex 502774-0891 mu-sd connector (pins are facing upwards).

Part of the problem is what I think is a bug in the board: micro sd has a different pin numbering from regular SD, but on the board identical pin numbers seem to be used for regular and micro SD. For example CS is connected to pin 1 of SD and micro SD, but for micro SD this should be pin 2. See http://elasticsheep.com/2010/01/reading-an-sd-card-with-an-atmega168/

I've cut traces 1-3 on my board, and connected CS to pin 2 and DI to pin 3 but the iotest application is still giving me this error:

Testing IO board SD card: Write...
Not in idle state after sending CMD8 (not an SD card?)
Didn't get a response from the disk
Set 512-byte block timed out

Now the mbed hangs. After rebooting (but keeping the SD card powered) I get:

Testing IO board SD card: Write...
(a few seconds delay)
Timeout waiting for v2.x card
Didn't get a response from the disk
Set 512-byte block timed out

I've tried two cards, a cheap ebay 4GB and a brand new class 10 Transcend 16 GB, same behaviour.

So, any ideas? Is there indeed a fault in the pcb?
Do I need any specific SD cards such as non-SDHC?
The above page says SPI mode is optional for micro SD, could that be it?

Thanks!
Joost


Replies (4)

RE: Micro SD card problem - Added by drogon over 10 years ago

I had the same issue - I was sent the wrong µSD card holder in the kit of parts (And a full-size SD card - Doh!) I whinged about it, but .. meh.. So rather than hack about with the pcb, at their suggestion I ended up buying the full-size one separately which I did, unsoldered the µ one and soldered on the full-size one. Works fine.

You've also hit what I think is the 2nd issue - In µSD cards the SPI interface is optional and I suspect it's simply not present in most new µSD's. It certainly wasn't on the ones I had.

Good luck with the rest of it!

-Gordon

RE: Micro SD card problem - Added by jaap over 10 years ago

Before anything else, try a 2GB card. Bigger cards run SDHC instead of SD, different protocols. By using a 2Gb card, you sure it's not a software issue.

This same issue has been discussed in this thread: http://redmine.laoslaser.org/boards/1/topics/689?r=694#message-694

Please note what the board designer says here: "I designed the microSD slot, tested it and it didn't work with the cards I had."

RE: Micro SD card problem - Added by joostn over 10 years ago

Yes I figured I'll just have to try a full size 2 GB card instead. Need to get a suitable connector.

But please do review the board layout for the micro SD connect, I'm quite sure it's misconnected currently.

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