Re: Repost: Is this a PC Floppy Interface Card?

[Rubywand <rubywand@swbell.net>]

Stingray writes ...
> 
> Rubywand wrote:
> 
> > Stingray writes ...
 ....

> > If it is
> > a floppy disk controller, you would not need to add any power supplies; the
> > power would come from your Apple II via the Slot.
> 
> Don't PC floppy disks REQUIRE an external power supply? They all have that
> little four pin power jack that plugs into the PCs power supply. I don't think
> that they are capable of drawing power through the ribbon cable like an Apple
> drive does.
> 

     True. Overlooked that. However, it would be easy for the board maker to
supply a ribbon cable which uses a few unneeded lines to feed a branching
power cable. That would be one way to allow using unmodified PC drives. Even
simpler would be a separate power cable ending in a sandwich plug which goes
to the motherboard and has pins for plugging in the power supply. Basically,
you can be pretty sure that the power would come from the Apple II. 

     If the ribbon cable came with the card, it probably went to an adaptor to
fit the regular edge card connector of a PC drive.

 ....

> >
> >      It seems unlikely that the card is intended to permit access to MS-DOS
> > formatted diskettes on an Apple II or that it can support 1.2MB HD drives.
> > The hardware on the card looks too simple. (It may support two-sided access
> > to regular 5.25" DD diskettes.)
> 
> That's a bummer, I was hoping it was for using a 1.44mb 3.5" PC floppy. I guess
> the only way to find out is to plug it in and see what happens.
>
 ....

     Well, as you observe, you would need to run +5V, +12V, and GND leads from
the Apple II to the PC drive power connector. Plus, you would need an adaptor
for the cable to connect to an old PC drive. So, a full-scale test would be a
hassle.

     There's a fairly low-risk check you can do. Remove the ribbon cable and
(with power off) plug the card into Slot 4. Turn ON the computer and boot a
DOS 3.3 diskette that will let you get to the Applesoft BASIC prompt. Do a
CALL -151 to get to the monitor.

     If you are trying this on a IIgs enter this code at 1000

1000: AD 2D C0 09 10 8D 2D C0 60

and enter 1000G

This should enable the ROM on the card in Slot 4.


     If your Apple II is not a IIgs you can skip the above.

     To view the contents of the ROM on the card, enter

C400L

     Look for this code next to some C4xx addresses ...

BD 8E C0
BD 8C C0
BD 8A C0

You will probably need to enter L a few times to list more of the ROM.

     If you find the code before running out of C4xx addresses, the card is
almost certainly a disk controller.


     On the other hard, it's the year 2000 and both real Apple Disk ][ drives
and real Apple Disk ][ controller cards are dirt cheap. So, the test may be
more bother than it's worth.


> 
> Thanks for responding, Rubywand.
 ....

     You're welcome. The card is an interesting puzzle. Maybe someone who
actually knows what it's for will post the answer.




Rubywand