Having the ability for a PC to read the file directly of a CF device is appealing - even if you need to write an application to interpret the data. The killer is that in a normal FAT file implementation for data logging you are always opening and closing the file thus writing too much to the FAT table -one method is to write one large file initially filled with 0xff's for the size of the flash device. The 8051 code on startup looks at the FAT table to find the start of the file then searches the file block by block to find a block full of 0xff's (that is the current end of file) the code can now write the new data from that point a block at a time and also writes the following block of 0xff's. Thus the 8051 can be powered up and down without killing the file system (hopefully!) and always appending the data to where it last left off. It would also be wise to timestamp the data so it can be pieced together again on the PC.

The PC can read this file (email it whatever) and a specially written application can scan the file , extract the data, format it then write it to a comma delimited file until it hits a block of 0xff's.


Simple!

See Dunfield Development Systems for a cut down FAT file system in 'C'. All in all should only chew up a few 'k' when done in 'C'.

Cheers

Russell