Mass Storage transfer speed

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Muis on Wed Nov 21 07:24:59 MST 2012
Using the LPC11U14 and LPCUSBlib 0.98, I created a Mass Storage device which reads data from SD card. The problem is that I'm not able to reach transfer rates above 250 kb/s, while a cheap off-the-shelf cardreader can easily accomplish 1 mb/s. Im not sure if it's the SPI rate, USB clock, or CPU speed which is the bottleneck, so a couple of questions:

     - SPI is running at 12 mhz, am I right that this should be enough?
     - Would it make a large difference to implement multi-block SPI transfer?
     - VIRTUAL_MEMORY_BLOCK_SIZE is 512 in the MassStorage example, would increasing it improve performance?
     - Is this CPU even capable of doing 1 mb/s transfer from MicroSD? If so, is there some example code?