You can also experiment with this chip...or one that provides much the same function by obtaining a packaged notebook computer USB floppy drive. My latest notebook computer came with NO floppy drive and as such I had to purchase one made by Sony. It has just such a chip inside.

Here is a data sheet for a FDD unit. It gives some nice info on how the 34 pin signal interface works.
http://www.beg-buerkle.de/support/H...F-A429.pdf

The defacto standard for floppy disk controllers was established back in the days when IBM introduced the first PC with the floppy being controlled by an NEC uPD765 chip. You may gain some information reading a uPD765 data sheet at the following link. Note that since the software drivers for floppy disks, have since the beginning, been contained in the ROM BIOS of the PC, it has been converntional practice that many follow-on floppy dick controllers used a software interface register set and command protocol derived from the original NEC chip.
http://ohlandl.kev009.com/floppy/uPD765.pdf

Data recovery from a floppy disk drive usually requires a PLL type circuit called a data separator. On chips like the uPD765 this was often built out-board on the PCBA. These days it is usually incorporated into the silicon. You may find this discussion on the subject interesting...
http://www.electronics-forum.net/design/Fl...41430.html

There is a catch-all of information regarding floppy disks and formats here at this link...
http://ohlandl.kev009.com/floppy/floppy_index.html

Note that conventional floppy disk controller interfaces done either on the PC motherboard or to the floppy disk adapter on the ISA bus used a DMA channel to transfer the sector data to/from the computer memory. This technique came about because chips such as the uPD756 had little or no FIFO buffering on board for the data flow path. The first PCs at 4.77 MHz had some difficulty being able to reliably read/write the data to/from the diskette controller at some 32 uSec per byte using program loops and thus DMA came to the rescue. Some later FDc designs, such as one I did for a product called the GiftBox Floppy disk controller, used wait state synchronization in conjunction with the repeat-block-move-I/O instructions that became available on the later PC/AT computers.

If you happen to pick a floppy disk controller that has a software register level interface similar to the original uPD765 a good place to look for ideas on how to write the software driver is to look to the IBM technical reference manual that was published in conjunction with the original PCs. These manuals had complete software listings, in 8088 assembler, for the ROM BIOS of these machines. If you are interested in seeing this send me an email....its been scanned.

Michael Karas