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Saelig uDrive module

I have been planning to hook up a micro SD card to an AVR for data logging, and today I came across a module with a micro SD socket:

The module takes care of the SD card, and you talk to it over a serial link. I was hoping that the module would handle a file system on the card, but it just provides sector read and write, and byte read and write.

Since this is the level one would use anyway if talking directly to the card, I am wondering if there is something else that I am not aware of that the module would insulate me from. Speed is not an issue in the application I have in mind.

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Pertti
Reply to
Pertti Kellomäki
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The major differences is that the module is 3.3v RS232 ASYNCHRONOUS serial, wheras the card itself is probably either SPI SYNCHRONOUS serial or the proprietary multi-bit superset of that.

Also the physical issues are taken care of for you. But in a pinch you can solder wires directly onto an full-size SD card anyway.

I think the type of serial interface is the big difference though - which to you have available, a spare UART to talk to the module, or a hardware SPI channel (or pins to bitbang more slowly) to do the synchronous SPI mode?

(For spi, you also need to check that the micro SD card to be used supports that basic mode - my understanding is that only the full sized SD cards are required to, but would not be surprised if the smaller ones do as well)

Reply to
cs_posting

Ok, so there seem to be good reasons to hide behind a module then, at least for prototyping. SPI mode seems to be optional for microSD cards (according to Wikipedia), the only required mode is 1-bit mode. I have no idea how painful it would be to talk with a card using the 1-bit mode, though.

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Pertti
Reply to
Pertti Kellomäki

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