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LPCUSBlib + FatFS + USB Write Error while powering down periodically

Question asked by TOJO MADAPPALLIL THOMAS on May 13, 2019
Latest reply on May 20, 2019 by TOJO MADAPPALLIL THOMAS




I have been using LPCUSBlib and FatFS in my project to support USB as a host. In my project, I store data to the USB device periodically. It was working smooth until I introduce a power save option.


 I tried to power down the USB when it is not in use. It saved me a lot of power conception. I was happy, and it looked working but some USB devices doesn’t like this power down. I found data loss on these USB’s. I loss the data which I write to the last file.


Starting Up

Create folder1->file1 and write some data

Create folder2->file2 and write some data

Create folder3->file3 and write some data


Power Down the USB


Power Up the USB

Append some data to folder1->file1

Append some data to folder2->file2

Append some data to folder3->file3


Power Down the USB


When I check the files, data in the file3 found missing.


Any help is appreciated.


Thanks in advance.