Floppy controller questions

---snip--- Hi One thing to consider is that you can unroll the loop and just fetch or write data and increment the pointer. Even on an 8080, this is reasonably fast. If you know the speed of the processor and the speed of the controller, you don't have to check the data ready bit every time. You just need to do it often enough to resync things. Another trick, if you are using a loop, is that you can make the loop partially unrolled. You only modify the counter once every few data read or writes. You do, say, 4 bytes at a time. Any odd amounts needed can be unrolled. Using any one of these tricks will get you in the range. On a PC, the main issue is that you need to shut down all interrupts and be aware of refresh if it uses memory cycles. On a processor that I was playing with, I found that the processor was too fast for the FDC chip. It was only running a 4 MHz instruction speed. Dwight