Customer need to compare the hardware platform for K21 and K22, if both using the same frequency external crystal/oscillator. For both chips with the same USB module, the USB related code should be same. The porting focus on hardware platform difference.
And I find there is USB stack for K22, which also include USB HOST MSD demo.
Please check below link for more detailed info:
Freescale bare metal (no OS) USB Stack Rev. 5
Wish it helps.
best regards
Ma Hui
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------