CompactFlash is a flash memory with an embedded controller that makes it look very much like an IDE device. In fact it has what's called True-IDE mode that makes it look exactly like a minature IDE disk. You read/write the disk using the 8 byte IDE task file and the 16 bit dta bus. The bus can programmatically be reduced to an 8 bit bus if you need to conserve pins.
See also:
/techref/member/rr-usa-p64/cf_inst.htm I have code available which operates as a: PIC data logger to CF Card file; the CF Card filesystem is updated; and the data is readable via Windows PC software.
See:
Questions: