USB Stack MSD host USB drive compatibility

[martindusek]

Hello,

I'm testing compatibility of USB drives with Freescale USB stack MSD host using msd_mfs_generic_test project project in Freescale USB stack 4.0.2 and Kinetis Full speed USB module.

Generally, how many USB drives should I expect to be compatible with MSD host?

Are there any specifications USB drives have to comply to in order to be compatible with Freescale's MSD host? What about file system on USB drive?

Are there any enhancements to make more USB drives compatible with MSD host?

[CarlosCasillas]

Hello Martin,

USB stack is based on the MSD specification; however, several USB sticks manufacturers don’t meet the specification (timing, endpoint handling, supported commands, access speed,etc). Thus, when a USB stick is out of specification, the embedded file-system libraries are unable to support all the variations such as non-embedded solution does (like Mac-OS or MS Windows). So, it may be required adding a considerable amount of code in order to support all the variations. USB Stack developers are continuously improving the MSD Host applications, testing more USB sticks for every release and applying workarounds if necessary. However, a universal workaround for this is very difficult to obtain because the huge variety of non-compliant USB sticks on the market.

Regarding the supported file system, it currently supports FAT16 and FAT32.

Hope this will be useful for you.

Best regards!

/Carlos