8" Disk drives - test-drb@ccmp.vtda.org

14 Jan 2002

On Mon, 14 Jan 2002, Tony Duell wrote:

...

 One quick question, are those normal or inverted signals? The PC floppy 
 Active-low (inverted, -ve logic, whatever you call it)

  adaptor seems to have all negative logic
(inverted) signals.  If they're
 really negative logic, it'll be possible to rewire a cable pretty easily,
 otherwise I'll need to put some inverting buffers on it. 
 No, it's just a cable. The only issues are :

 1) The data rate is 500kbps (same as a HD PC drive) in DD mode, so you
 can't use an XT controller (not that you'd want to...)

 2) The Low Current signal. This is a reduce-write-current input that
 should be asserted (pulled low) when writing to tracks >43. Most PC
 controllers can't supply that signal directly. If you're just wanting to
 read disks, then it's not important, though.

 3) Many PC controllers have problems with single-density operation...

OK, A couple more issues I wanted to ask about:

1) Should I use "Read Data Composite" or "Read Data Separated"?
What's the
difference?

2) Do I need to do anything with the "Clock Separated"? I'm guessing
that's an output that goes with the Read Data Composite/Separated outputs

3) Can I just connect the 'head load' to 'ready' or is 'ready'
dependant
upon the heads being loaded?

Thanks a TON for the info!

-- Pat

...
  -tony