I am using a BF707 to write files to a micro sd card. My files a 4MB in size. My sd card clock is 50MHz and I have 4 data lines, so I should be able to write at least 5 files per second I thought. But in reality I reach only 2 files max and often I see the time increasing and I am writing only 1 fps.
I used the Analog Device rsi.c files, and the Fatfs the write in fat32 to the card.
Does any one know how I can improve the performance, or what is the reason why my performance varies som much and why is it even in best case so much lower than I had expected from a clock of 50MHz.
Hi Rene,Apologies for the delay in response. Can you please let me know whether you are using custom board or EZ-kit? Also, can you please share the SD Card part number? How are you measuring the SD card's speed? We would suggest you to test the performance by reading/writing large files. BTW, I believe the following thread might be of help.
This thread explains how the SD Card clock can be set based on the requirement.ez.analog.com/.../sd-card-clock-frequencyRegards,Lalitha S
I am sorry that I did not saw your reply earlier. I am using our own customised board.
What I found that it very dependend on the brand of the SD card. Further out of tests we noticed that at the moment I create a new folder the writing goes fast, but slows down at te moment when there are more files inside the folder.
I found on other postings (not AD or Blackfin) releated that other people have simular issues with writing files to sd cards.