Could you try to format the USB drive and see what happens? What size is the drive? If you try and read more than 5 characters the first time, does it work? Could you try to read all 500 and see if that works?
Writing to the drive is no problem.
Even copying files, renaming files, … no problem.
I just tested it: reading 150 chars: no problem.
The 500 chars was just a test to debug my program.
That’s why I was reading only 5 bytes at a time.
The file could be much shorter, or longer: it’s generated by the customer.
Some other interresting point:
the “Read Status Register” J command, always returns $00. Even when the U1 drive is mounted (and logging) or not.
the set “Current Time and date” S command does not work:
When sending " S 34212002" (your example in the manual), it will return !00. But when you look at the Date created on a PC, it’s always 31 Dec 1978 23:00
I’m controlling the alfat module from a atXmega128