[Coco] CocoSDC won't stay off

[John Goerzen]

Darren A <mechacoco at ...> writes:

> 
> On Wed, Dec 3, 2014 at 7:09 AM, John Goerzen wrote:
> 
> >
> > Is it possible this explanation is consistent with BACKUP 0 TO 0 but not
> > BACKUP 0 TO 1 working?
> >
> 
> No. If BACKUP 0 TO 0 works then it is probably not a problem with the CPU.

That's what I thought too, but now the plot thickens.

So I have a second CoCo on hand now (see the thread about the mystery
side-switches).  However, on this one, BACKUP 0 TO 1 DOES work.  D19.BIN and
such still do not (it always seems to flip DRIVE 0 to ON even if I had
previously said DRIVE 0, OFF).

That's still annoying, since this is the best utility I know to copy files
one at a time from one disk to another.

> 
> Try this test. With the same configuration (SDC in slot 1, floppy
> controller in slot 4 and switch set to 1) enter the following:
> 
> A=65407
> POKE A,3
> PRINT PEEK (A)
> POKE A,0
> PRINT PEEK (A)

Same on both CoCos:

The first PRINT shows 3, and the second shows 0.  (As, I guess, I would expect.)

> 
> What values do you get for each Peek?
> After entering these are you still able to use the DRIVE command to display
> the SDC settings?

Yes, on both CoCos.

John