On Wed, Feb 16, 2011 at 10:03 AM, Tony Firshman <[email protected]> wrote:
> 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. http://www.computer-engineering.org/ps2protocol/ http://www.computer-engineering.org/ps2keyboard/ We've come a long way since the 90s ;) Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
