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USB/SD mass storage device example bf547M

Question asked by romanlomoff on Mar 27, 2015
Latest reply on Apr 6, 2015 by romanlomoff


We have our custom BF547M-based board and we are trying to run example mass storage device for bf548.

We have the sd card on our device and we try to read/write data through usb.

Read data from sd is successful, but if try to write data then the Windows application is hang.

When I reloaded the project, on sd card I saw the file which I tried to write.

But file was with error.

Only the first 4 Kbytes written correctly.

If I want to write file not more than 4 Kbytes, when write is succesful without problem.

But if more than 4 Kbytes, then only first 4 Kbytes write correctly.

I found in the file "mass_storage_app"  #define USB_BUFF_SIZE 4096.

If to change this define, then exactly as many bytes written correctly.

If to use ram disk then have no problem read/write.

What is the problem ???