lpc1768 writing time to usb flash memory

hi
i am working with lpc1768 in usb host mode
Initially I was open seven text files by fopen command
Then write a string like "abcdefgh" by the fputs command within seven text files
Before writing command first turn on one led and after seven write comman turn off led
By measuring the time of high and low on led pin I realized that this time is the size of about two seconds.
I want to know is why?
Thanks for your help

More questions in this forum