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Micro SD card problem

Added by joostn over 9 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 9 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 9 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 9 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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