USB flash memory and drive

payon · ‎2016-09-11

Posted on September 11, 2016 at 21:43

Hello,

I hope I have an easy question. I would like to use an SD card together with my STM32F10x processor. The SD card should be used as an external flash memory.

However, when the PCB consisting of the SD card and STM32 is connected via USB to the PC, it should be shown as a USB flash drive.

And both, the µC and PC should have access to write / read files.

Is this posible with the processor type, and which mode is it?

And do I need OTG for this (specifically the F105/107)?

Marcus

Tesla DeLorean · ‎2016-09-11

Posted on September 11, 2016 at 22:56

Well it is certainly possible to provide MSC type access to the SD card for the PC, and it is also possible to access the the SD card via FatFs locally. What is probably intractably difficult is providing read/write access to both simultaneously. The problems stem from keeping the file system coherent, and caching/connectivity on the PC/MSC side. If one mode is limited to Read-Only things might at least be workable.

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