Thomka.es@XEROX.ARPA (07/27/84)
I am familiar with the keyboard encoder used with the Apple 2 piece keyboard design. But the number you stated (the 931 number) I guess, is the Apple designated number. If you hear that there is an off-the-shelf (meaning off any electronics shop shelf) chip that can be used, don't believe it. There is a family of related chips but you can't use the one that really is off-the-shelf. The manufacturer's number is the General Inst. # AY-5-3600 number. I looked into this chip and found that there is an off-the-shelf AY-5-3600. But you do not want to buy it. The reason is that Apple did not use the off-the-shelf chip. The AY-5-3600 can be bought several ways: 1) the off-the-shelf way, 2) made with a custom internal ROM mask 3) made to utilize an externam ROM (that's the AY-5-3600-PRO) The internal ROM matrix of the off-the-shelf AY-5-3600 is so drastically different from the one that Apple has inside their custom internals that you will get some VERY WEIRD characters if you type with it. It will not hurt anything, just weird. For example, using the regular Apple 2 piece "piggy-back" circuitry and keyboard with the off-the-shelf AY-5-3600, if you try to type QWERTY you will get @WSXctrl-^ Apple bought the second type. Probably because the chip design of the AY-5-3600 is really nice (except it doesn't give n key rollover) and that the making of the custom version is very cheap (I priced it at $1500). Also the regular version of the AY-5-3600 doesn't give some control characters at their expected position. For example, the only way a ctrl-U (the right arrow) can be done is by pressing CTRL/SHIFT 3; and if that isn't weird enough, the ESC character (ctrl-[) can only be done by pressing CTRL/SHIFT 8. The easiest solution for you would be to get an unwanted Apple encoder chip, or you can even buy them at some of the Apple repair shops for about $14. I've done that. Another solution, but more expensive, is to but an after-market replacment keyboard for the Apple. That way you can get some of the "trick" functions some of them provide. Chuck