I have an embedded system that uses SPI mode to talk to an SD card. The system works fine for regular 1 or 2GByte SanDisk SD cards but when using 2GB SanDisk Ultra II SD cards the card becomes unusable.
Here is an example: Buy a 2GB Ultra II SD card, put it into a Mac or PC. The card works fine. Put the card into my device and format it. Format fails - cannot write to card. Put the card into PC, now card has no format and refuses to format.
I am using 2.7 volt signals and the card still responds with all its configuration data, so the controller chip seems intact. But when I read a sector I just get incrementing 32bit numbers (like sector numbers used for unique sector testing).
Before I start blowing up cards trying to debug this problem, I was hoping someone else has run into this already.
I understand roughly where you're coming from as I'm developing for SD via SPI right now.
The closest I've seen to this is with CF cards and partitions, and digital cameras. When developing for the CF cards I wiped most of the sector 0's on most of my cards. While the cards could be used in a PC or PDA, they wouldn't work in my Fuji S7000 digital camera. What I ended up doing was buying an IDE adapter so that the CF cards could be addressed as a physical device (all devices in card USB readers are always logical devices so you never get to the actual card itself). And then once configured as a hard disk I then used fdisk in DOS to repartition the cards. Now they work again in the camera. No amount of 'initialising' in the camera or 'formatting' in the USB reader previously made any difference. I had destroyed the most fundamental information that the user would never have access to.
I'm just playing about in my mind that this is a physical/logical device problem you're having. I'm aware of this with my SD cards here that I use for testing, so always backup the physical sector 0 and the MBR before overwriting those sectors. ....just in case.
There is also another thing to consider. Not all SD cards are the same.... I have two identical cards from the same manufacturer here and one misbehaves, and the other works perfectly. There's alot of cards out there that don't follow the Sandisk document to the letter.
I also have here a 128MB Maxell card which is about 4-years old, and it CMD0/CMD1 initialises ok, but whenever you try to read or write sectors it just returns an internal read error. Yet it works fine in the USB reader and PDA. I can't get it to work though.
I'm not sure what to suggest but hopefully what I've said here with get your mind racing when you're trying to sleep tonight ;-) I'm still at the very fundamental implementation stage right now.
This is also something to look at;
formatting link
Hope that helps :-)
Alison
ps. also this if you're going back to the implementation stage and don't have it at hand; type the file below into Google and save it, as these are disappearing fast. Sandisk is kind of purging the net of these;
Another idea. Your reader on your PC may be suspect. Some go a bit weird with the big media cards. That one is documented on some on the digital photography and PDA forums.
Thanks for the links, thats some good stuff... I ordered a new Ultra II SD card and I am going to see how it behaves. I have 4 2GByte Ultra II SD cards that dont work in any reader I can get my hands on, but my regular 2GB cards are fine. The customers that sent them to me claimed they used to work until my product tried to format them.
One card appears to have taken the format to a large extent, but also now refuses to write. I checked the write protect bits and the are ok.
Note that I found that some other SD cards need more than 8 dummy clock cycles after releasing ChipSelect to work reliably.
-howy
Alis> I understand roughly where you're coming from as I'm developing for SD via
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.