AnsweredAssumed Answered

SDIO microSD speedup

Question asked by jasonas.matas on Aug 25, 2015
Latest reply on Aug 25, 2015 by Clive One
Hey I am making a microSD card logger, it is going to run on a battery so the power  consumpion is of big importance and because of that microSD card speed also matters a lot. I've found the program H2testw which is used to test the SD card speed. I've tested 5 microSD cards 64Mb (Unknown), 2Gb(4 Class), 4Gb(4 Class), 8Gb(4 Class) and 16Gb (10 class). The results were:
64Mb - Read: 0.99Mb/s, Write: 879Kb/s
2Gb - Read: 0.99Mb/s, Write: 927Kb/s
4Gb - Read: 0.99Mb/s, Write: 581Kb/s
8Gb - Read: 0.99Mb/s, Write: 888Kb/s
16Gb - Read: 0.891Mb/s, Write: 896Kb/s

And sometime even lower speeds...

Example from H2testw:
Warning: Only 200 of 1882 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 788 KByte/s
Reading speed: 871 KByte/s
H2testw v1.4

I've tried to test them with the code Clive1 provided "asr_ahmed_sdio.hex", but I couldn't find a way to change the SWV clock (2000kHz) And nothing happens.

Is there a way to speed up these microSD cards, because as I check other people manage to get up to:
=Writing speed: 3.48 MByte/s
=Reading speed: 14.1 MByte/s

But in my case I cant get reading speed higher than a megabyte. So does anybody have any ideas?