I'm just curious, is it typical to get sporadic (albeit rare) SD card write errors when executing over SPI at 16 MHz.
Here is the set up:
SDHC Class 4 card (8 GB)
Operating over SPIC (if it's relevant)
No File-System, writing raw to card.
Essentially I am doing some testing right now to determine actual data-transfer rates we can achieve and
am simply writing continuous sectors to the SD card. I am not using multi-block writes, just the CMD24 write-block and updating the info on sector address/error counts every 800 or so writes (just some division of the storage amount.)
Basically what seems to be happening is very rarely the card will either time-out or return some error code. When this happens I simply give the card a minor delay and send the command again. Typically it appears that I will have to send the command twice after the initial failure to get it to succeed (not sure if this is systematically relevant). Letting this run for quite some time I find that we are getting approximately a 0.04% error rate (very minor, but still there).
I was wondering if this is typical? Is it possibly due to signal integrity on the SPI module when operating at 16 MHz or perhaps something with the cards?
I am waiting for the card to not be busy before each write command.
Any info will be much appreciated,