Re: IIe not recognizing Unidisk drive

[dempson@actrix.gen.nz (David Empson)]

Kyle Boyd <kylekboyd@gmail.com> wrote:

> On Aug 19, 3:26 pm, Alex Freed <alex_n...@alexfreed.com> wrote:
> > On 8/19/2011 12:14 PM, Kyle Boyd wrote:
> >
> > > On Aug 19, 12:56 pm, Eric Rucker<bhtoo...@gmail.com>  wrote:
> > >> Make sure the card is seated properly, and the drive is plugged in
> > >> tightly.
> >
> > >> It sounds like it's not seeing the card or any drives on it at all,
> > >> because it's dropping straight into BASIC - what a //e does when
> > >> there's no disk devices.
> >
> > > Thanks for the reply.  Unfortunately, I've already triple-checked that
> > > the card is seated firmly and the drive is plugged into the port
> > > firmly.
> >
> > There are 2 main possibilities:
> > 1. The "inspection" broke the interface card. Not very likely as TTL
> > chips are robust.
> >
> > 2. The card doesn't make proper contact with the slot.
> >
> > The things to try:
> > 1. remove and insert the card a few times. Contacts may oxidize in 20 years.
> >
> > 2. Assuming the card is in slot 6, type
> > call -151
> > c600l
> >
> > if this lists reasonable assembly, the card is it least visible to the
> > CPU. If you get a lot of "???", it is not.
> 
> The card is in slot 6 and when I tried the command I did get back what
> looks like assembly (first line is: C600- A2 20   LDX   #$20).

That's the correct first two bytes. If the rest of the firmware looks
OK, and the problem was with the drive rather than the controller, then
the IIe should appear to hang when trying to boot, since the drive
firmware will be attempting to boot from the nonexistent drive. The Disk
][ and UniDisk 5.25" controller firmware has no concept of passing boot
control back to the firmware if it is unable to proceed.

To be recognised by the Autostart firmware, the card firmware must
contain these bytes (for slot 6):

C601: 20
C603: 00
C605: 03
C607: 3C (only required for a ][+ or unenhanced IIe)

If those four bytes match, then the firmware will jump to $C600 during
the startup sequence.

Since your IIe is behaving like the card isn't there, and the first ID
byte is correct, I expect the second or third ID byte is wrong.

> I'll try another slot and also cleaning the contacts although they are
> spotless already (this machine is in absolutely astonishingly
> immaculate condition).

-- 
David Empson
dempson@actrix.gen.nz