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Very Slow SD Card Access

Question asked by weblar on Dec 17, 2013
Latest reply on Feb 8, 2014 by Mark Butcher

Hi,

 

I have an existing project running on my Kinetis K60 which uses the FatFS file system with the USB stack running as an MSD device. I'm using the ESDHC peripheral connected to a class 4 SD card as the storage device for the FatFS and MSD.

 

If I attempt to copy a file onto the USB MSD from within Windows, I get a transfer rate of about 60 kilobits/s which I would consider dreadfully slow.

 

Has anyone had any success with getting the ESDHC peripheral to run quickly? I'm thinking that there must be something wrong in my initialization routine (code taken from Freescale examples) such as in the SYSCTL register where I set the ESDHC clock divisor and prescalar however changing the values to make the clock faster makes little difference.

 

I purposefully haven't posted any code as there is a lot of it but I can where necessary.

 

Thanks in advance,

K

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