[parisc-linux] Parallel port hardware (fwd)

[Sandy Harris]

"Bill Katz (William)" wrote:

> Sandy Harris wrote:
> |Can anyone point me to info on the electrical properties of the parallel ports
> |on 712 or 715 machines?
> |
> |I'm thinking that 8 715s might make an interesting parallel engine, but the cable device
> |only works if the parallel port's control lines are implemented as open collector TTL.
> |Where can I discover whether they are?
> 
> Early 715s ...
> 
> Later 715s (/64, /80, /100) and all 712s use Lasi.  From the chip ERS
> (not published, it's mostly electrical stuff) Data strobe, autofeed,
> parinit, and select
> 
> The ones that connect to pins 1, 14, 16, and 17 are open collector.

Bingo! Those are exactly the four lines used for the Wapers parallel stuff.

http://garage.ecn.purdue.edu/~papers/WAPERS/