Re: Commodore drives can be controlled on Apple II serial!

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

Supertimer <supertimer@aol.com> wrote:

> dougkalley@aol.com (DougKalley) wrote:
> 
> >>Also, as someone indicated, the Commodore serial port wasn't RS-232.
> >>Implementing this on a dedicated RS-232 port wouldn't be feasible, but it
> >
> >If my memory is correct the c= output is a cut down IEEE-488. The 232
> >comes out of the user port which isn't true 232C. Would it be easier run
> >it out of a floppy i/o, the a2 to 1571 line would have to be changed I
> >assume? If you have to code a program to do it I think that route makes
> >more sense.
> 
> Good idea!  Can the Smartport be reprogrammed to run the Commodore
> drives?  If serial is not sufficient, this is THE bidirectional parallel
> interface on the GS and the IIc & IIc+ (optional on the IIe).

SmartPort is serial, not parallel.  It also has several major
limitations: all data bytes transferred must have bit 7 set, and the
data rate is fixed (4 microseconds per bit cell, or 2 microseconds for
Apple 3.5 drives).

The only exception to this is the phase lines, which give you a four-bit
parallel output that can be controlled directly by software, and
probably the sense line, which gives you a one bit direct input.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand