New CF-Card drivers can be made relatively simple.
Have a look at the supplied drivers.
There are always a few files needed :
|•||A config file in the format : CONFIG_XXX.bas|
|•||FlashCardDrive_XXX.lbx is derived from the LIB file|
XXX stands for the name of your driver.
At the AVR-DOS web you can find more drivers.
See also: AVR-DOS File System