SD Card compatibility

[khoney]

I thought it might be useful to have a thread related to SD card issues when used in SPI mode. I've been using SPI mode for SD card access with the MOD5270 and the Nano module for a few years now. I recently decided to try a Swissbit uSDHC card (16GB) for use in an application where improved reliability is beneficial.

Swissbit claims to have improved reliability SD and SDHC cards. They are supposed to be more tolerant of power failure, have better wear leveling, etc. They are much more expensive than your typical SD card.

So, I ordered a Swissbit 16GB uSD card to use instead of my SanDisk 16GB. I am doing some real-time data collection and storage in my app. My app is writing a file every minute, but lo and behold, the Swissbit fails after writing a few files. All of my other cards just keep writing until I power down. Very weird. I haven't tracked the problem down and frankly don't have the time or money to do so right now, so I guess I'll just keep using cheap cards.

If anyone has had a similar experience with Swissbit and can provide any guidance, I'd appreciate it.

BTW, Swissbit says it is fully compatible with SPI mode, and I am well within the operating voltage and have plenty of power supply current.

[dciliske]

Part number? Is this in the devboard?

[pbreed]

Kinda off topic.....
I had a SD card logging app where it could crash (literally this was a flying device) and the data I really wanted was the data just before the crash....
I could never make the regular file system flush fast enough, so I started just writing directly to the sectors on the SD card and logged data that way.....
So if crash resistance reliability is what you are looking for I think changing how you write to the card might be more beneficial than a high reliability card....


Paul

[khoney]

@dan - The part number is SFSD016GN1BM1TO-I-HG-111-STD (Mouser part# 922-604586). It is not part of the devboard - I'm using it in our end system.

@paul - This is the first card I've ever had a problem with (granted, I haven't tried a lot of them). It does make me think I should buy some other vendors' cards to try though. I have read about different cards handling their sleep mode differently, affecting throughput. However, this is a very low bandwidth update (~20KB/sec). I'm not really expecting anyone to figure out why this happens - it's more of a caution to others who might be considering using this card. If I do ever figure out the cause, I will update this thread.