Hello,
--- On Tue, 6/9/09, Scott Holder <sc...@iamscott.net> wrote: > The Mac Plus/etc mouse is a pretty dumb device generally > speaking - the sensors are wired straight into a 6522 which generated an > interrupt whenever the mouse moved a notch any direction and a line > to sense the button. >From what I can tell, there was also a Zilog 8530 Serial Communications Chip >involved as well. Apparently, the Mac Plus mouse consisted of five electromechanical components: a button, and four optical encoders. The mouse button was wired to the 6522 VIA you mentioned while the encoders were connected to the 8530 SCC. > Pretty simple design, but not very flexible. It worked for the > one design of mouse, and not much else. Yes, it looks like Apple wrung about all they could out of the off-the-shelf components they used in the early Macs in an effort to cut down on costs. Not to say that what they were able to achieve with what they had wasn't amazing, just that they had taken it as far as it could go. I had always wondered what had prompted the transition from the Mac Plus's RS-422/6522 keyboard and mouse to the ADB keyboard and mouse of the SE. Apple seems to have been looking for greater flexibility for mice and keyboards while maintaining low cost: ADB gave them both. >If you *really* want the nitty-gritty, then you can also read >http://developer.apple.com/documentation/mac/Devices/Devices-205.html Thank you for that link. Does anyone know if there was a similar breakdown in the early edition (1985/86) "Inside Macintosh" books detailing how the pre-SE model Macs communicated with the keyboard and mouse? Best, James Fraser --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to vintage-macs@googlegroups.com To unsubscribe from this group, send email to vintage-macs-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/vintage-macs?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
