Plastic wrote, on 16/Feb/11 14:48 | Feb16:
On Wed, Feb 16, 2011 at 8:27 AM, Tony Firshman<[email protected]> wrote:
Plastic wrote, on 16/Feb/11 14:09 | Feb16:
Fun, huh? :)
It was particularly good fun with sH using similar decoding chips.
Firstly we *knew* we could use three pins only to output the 8 bit keyrow.
However Laurence then realised that the *same* three select lines could be
used to read 8 separate input lines. This saved us ten Pic pins!
It actually was the reason for many extra functions (spare RS232, DCD,
Turbo and keylock). We simply wanted to fill all eight input lines!
I haven't ever owned a SuperHermes, but I have read the manual. It is a fine
piece of efficient and clever design, befitting the QL. Kudos to you and
Lau.
It's just the sort of thing I'd like to build in due course... Though in
this day and age, supporting PS2 keyboards instead of the 5-pin DIN
keyboards might be the only worthy upgrade.
Any prospect, USBWiz thread, that the USB driver could support a USB class
keyboard?
sH was designed and sold many years before PS/2 keyboards were around.
It is a tribute to Lau's code that they work out of the box with the std
adapter. I wonder whether Di-ren and the others do?
Oddly designing code for these keyboards is very far from trivial. There
are oddities and bugs. When we came across these, no keyboard
manufacturer would assist. "We sent a lot of money working on these
these and we will not tell you" was Cherry's response.
Tony
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