Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-lcc!ames!ucbcad!ucbvax!cbatt!neoucom!wtm From: wtm@neoucom.UUCP (Bill Mayhew) Newsgroups: comp.sys.cbm Subject: Re: M1 Mouse Message-ID: <352@neoucom.UUCP> Date: Mon, 5-Jan-87 09:27:36 EST Article-I.D.: neoucom.352 Posted: Mon Jan 5 09:27:36 1987 Date-Received: Mon, 5-Jan-87 21:53:30 EST References: <1837@sunybcs.UUCP> Organization: Northeastern Ohio Universities College of Medicine Lines: 43 Summary: How the 1350 mouse works. Hi Devon, et al; The 1350 mouse for the C64/C128 is the same as the mouse that plugs into the Amiga. It has two IR LEDs that sine though a chopper wheel onto 4 photo transistors (two per axis). The transistors are set up in an arragnement such that as one moves the mouse, they generate sqare waves that are in quadrature phase relationship. That is to say that as one moves the mouse forward, one transistor's squarewave will lead the other by 90 degress. Reversing the mouse direction will cause the phase to switch to lagging by 90 degress. The using one transistor output as a trigger makes it possible to determine which direction the mouse is moving depending on whether the other transistor's output is high or low at the time of the trigger. The number of triggers per second is, of course, directly proportional to the speed the mouse is moving. Now, for the neat part. Since the mouse has four digital outputs, these go to the same four pins as the joystick contacts. It is possible to simply plug in the mouse and have it sort of work like a joystick. One one rolls the mouse, it is like repeatedly bumping the joystick lever. As you might guess, this doesn't work very well. It is possible for software to look at what is happening and figure out what sort of input device is there by the type of pulses coming in, but it is really easier to just have the user indicate whether the mouse or joystick is in use. The new Commodore mouse is model 1351. This one is especially for the C64/128 and comes with a GEOS update disk (so wait before you download all that stuff from Quantum Link). Reportedly the 1351 has some electronic goodies inside or something that makes it quite different. My parents just got a 1351 for their C64 yesterday and I haven't gotten a chance to go over to their place and disect it yet. --Bill Bill Mayhew Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44227 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbatt!neoucom!wtm)