Z80 home brew with FDC

On Sun, 21 Sep 2008 10:42:46 pm Andrew Lynch wrote: I'd like to see if the data separator on the FDC-1 for the SYM-1 would work on the 765. The FDC-1 uses a FD179x controller and it appears it uses the same data clock and raw data inputs as the 765. I've built the FDC-1 for my SYM-1 last week and it works a treat, in both FM and MFM modes and on 720k 3.5" disks. I used an SMC FDC1797 from an old word processor. The board it came off had a 9229 on it so I think there's a good chance the circuit will work. The decoder is made up of a 74LS197 (clock divider), a dual 74LS74 flip-flop, both used, a 74LS163 counter and an inverter. There are also some open collector NAND gates to select the clock rate for either 8" or 5.25" drives. It'll use more individual IC packages, but they're *much* easier to find. The circuits are, of course, at 6502.org: http://6502.org/users/dallas/SYM/SYMDOS2/fdc_sheet1.pdf http://6502.org/users/dallas/SYM/SYMDOS2/fdc_sheet2.pdf Thanks for that link to the SMC datasheet too. I'll give it a good looking over when it's downloaded. I was never 100% clear on the format procedure given in the Intel datasheet, so hopefully the SMC one will be a little better! Thanks, Alexis.