Re: Daisy chaining a Disk ][

[Patrick Schaefer <pa.schaefer@fz-juelich.de>]

John E Townsend wrote:

> too hard to do.  If anyone knows how to do this and can give me some
> pointers, that would save me a lot of work.  Thanks!

Look for the pinout of the 19pin connector (DuoDisk Interface, from
Technotes or FAQ). There are two lines, called -E1 and -E2 or -Enable1
and -Enable2.

Drive 1 uses -E1 as its enable signal. Connect -E2 to the second DB19's
-E1 pin, then the next drive will think it is -E1.

The Apple /// does the same, but with four drive select lines. One is
used internally, the others are shifted on the Disk /// Analog Board.
DS1 is used, DS2 becomes DS1, DS3 becomes DS2, and so on. 

This scheme is not compatible with smart port daisy chaining! With an
Unidisk controller only one Disk II is supported, and only as the last
device in the chain.


Patrick