Thanks for the pointer. I assume with this kind of setup, the strategy is to write 512bytes or so to EEPROM, (in my case 14.2 records) actually 14 records, and I guess nothing goes in the last '.2'.. (also what happens when I read it back? Does the extra unused space show up in read data as $ffff or something?)

Then, a routine writes from EEPROM to the SD card. Then we'd increment the sector on the SD card and keep going?

I see that there is code available to write to FAT 16 formatted cards also - for my project this would be a big benefit. However, I don't know much about the SD formats, etc.

1. Are SD cards pre-formatted as Fat16?
2. If it is not formatted as FAT16, is there ANY way to read the data from a PC?
3. What does 'write only one file' mean? I assume just a contigous block of incrementing addresses?

Why does one use SHIFTIN or SHIFTOUT?? Is it for SPI mode?

Tom