Apple Mouse
| Apple Mouse | |
|---|---|
 |
|
| M0100 mice: platinum (Macintosh Plus) and beige (Macintosh 128K/512K) | |
| Manufacturer | Apple Computer, Inc. (boards built by Alps Electric and by Mitsumi) |
| Type | Computer mouse |
| Interface | DB-9 quadrature |
| Compatible | Macintosh 128K to Macintosh Plus; Macintosh XL; Apple IIc and Apple IIe with some variants only (see below) |
| Successor | Apple Desktop Bus Mouse |
| Model | M0100 |
The Apple Mouse (model M0100) is the one-button mouse of the Macintosh before the Apple Desktop Bus. It has an opto-mechanical ball mechanism and a DB-9 connector carrying the raw quadrature signals; there is no microprocessor in the mouse.[1]
Apple kept the M0100 model number while the internal electronics changed, and the variants are not electrically equivalent. That is why some M0100s work on an Apple IIc and others do not; see Apple Mouse IIc.[2]
How it works
[edit | edit source]Apple describes the mechanism in the Guide to the Macintosh Family Hardware.[1] A rubber-coated steel ball turns two capstans, each connected to a slotted interrupter wheel, one for the X axis and one for the Y axis. Two beams of infrared light shine through the slots onto two phototransistors, offset so that as the wheel turns they produce two square waves 90° out of phase: the interrupt signal and the quadrature signal. The quadrature signal leads the interrupt signal by 90° when the wheel turns one way and trails it when it turns the other.
In the Macintosh Plus the interrupt signals X1 and Y1 go to the DCDA and DCDB inputs of the SCC, and the quadrature signals X2 and Y2 go to inputs of the VIA's Data register B. When the SCC receives a mouse interrupt it interrupts the CPU; the mouse driver reads the SCC to find which signal caused it and on which edge, then reads the VIA for the state of the matching quadrature signal.[1]
| Mouse interrupt | Mouse quadrature | Mouse motion |
|---|---|---|
| X1 rising edge | X2 low | Left |
| X2 high | Right | |
| Y1 rising edge | Y2 low | Down |
| Y2 high | Up | |
| X1 falling edge | X2 low | Right |
| X2 high | Left | |
| Y1 falling edge | Y2 low | Up |
| Y2 high | Down |
Direction depends on the phase between the two signals on each axis, so a fault that upsets that phase on one axis makes the pointer move the wrong way on that axis.
The button is a push button that grounds pin 7. Software reads it at bit 3 of VIA Data register B, where 0 means the button is down, once in each vertical blanking interrupt; the delay between checks debounces it. Apple notes that the mouse is a relative-motion device: it "doesn't report where it is, only how far and in which direction it's moving".[1]
Connector
[edit | edit source]| Pin | Signal | Description |
|---|---|---|
| 1 | GND | Ground |
| 2 | +5 V | +5 volts |
| 3 | GND | Ground |
| 4 | MSE.X2 | Mouse X2 (quadrature signal) |
| 5 | MSE.X1 | Mouse X1 (interrupt signal) |
| 6 | n.c. | Not connected |
| 7 | MSE.SW | Mouse switch |
| 8 | MSE.Y2 | Mouse Y2 (quadrature signal) |
| 9 | MSE.Y1 | Mouse Y1 (interrupt signal) |
Apple gives no current figure for the mouse itself, but all devices connected to a Macintosh Plus must not draw more than 200 mA in total at +5 V from all connectors.[1]
Internal variants
[edit | edit source]Glenn Anderson opened four M0100s, drew schematics of them and tested them. The difference that matters is the output stage:[2]
| Board | Screws | Output IC | Output type | Works on Apple IIc |
|---|---|---|---|---|
| Alps | 1 | 74LS14 hex Schmitt-trigger inverter | Push-pull | Yes |
| Alps circuitry, Apple-silkscreened board | 1 | 74LS14 | Push-pull | Yes, confirmed on an early A2S4000 IIc |
| Older "Made in U.S.A.", Apple-marked board, older-style plug | 2 | None: 3-pin optical sensors with push-pull outputs, no buffer IC or pull-ups | Push-pull | Yes |
| Mitsumi | 2 | µPC339 quad comparator (an LM339) with 3.3 kΩ pull-ups | Open collector | No; see Apple Mouse IIc |
The cords differ in part number between variants, and so do the board connectors. Anderson also cites Apple's archived note "Mouse Compatibility: Macintosh Plus and Apple II Computers", which distinguishes a mouse "Made in the US" that works on both machines from one "Made in Japan"; these match the Alps and Mitsumi labels. The label and the screw count identify a Mitsumi mouse without opening it.[2]
Maintenance
[edit | edit source]- Turn the retaining ring on the underside and remove it and the ball.
- Clean the ball and dry it fully.
- Clean the capstans with a swab and isopropyl alcohol.
- Clear dust from the interrupter wheel slots and the emitters and detectors on both axes.
A pointer that jumps or reverses on one axis points to that axis's wheel, emitter or detector (see Table 7-1 above); the two axes are built the same way, so the working one can be compared with the faulty one. The button is checked by measuring pin 7 to ground with the button held down. For an intermittent fault, check each conductor for continuity while flexing the cord where it enters the shell.
Related models
[edit | edit source]Deskthority lists the M0100, A2M4015, A2M4035 and A2M2050 together as the same mouse sold under different part numbers.[3] Anderson reports that an Apple Mouse IIe (A2M2070) is identical to the Alps M0100 apart from its label.[2] Apple's Macintosh XL parts list includes a "Macintosh Mouse", 661-96155, in place of the Lisa Mouse.[4]
- Apple Mouse IIc: the Apple IIc compatibility problem and its fixes
- Apple Mouse IIe: the Apple IIe version
- Apple Lisa Mouse: the earlier A9M0050
See also
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Apple Computer, Guide to the Macintosh Family Hardware, second edition, Addison-Wesley, 1990, chapter 7, "Macintosh Plus Mouse and Keyboard", pp. 275-278: the mechanism, Table 7-1 (mouse-motion signals), the button, the relative-motion note, Figure 7-2 and Table 7-2 (DB-9 connector) and the 200 mA limit. Hosted as File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.
- ↑ 2.0 2.1 2.2 2.3 2.4 Glenn Anderson, "Apple IIc mouse compatibility: some details, schematics, and a chip swap to fix compatibility", TinkerDifferent, from 15 September 2024. Four M0100 mice opened, drawn as KiCad schematics and tested on an Apple IIc, an Apple IIe with mouse card and a Macintosh Plus. Community research, cited as a secondary source.
- ↑ "Apple Mouse", Deskthority wiki. Lists Apple M0100, A2M4015, A2M4035 and A2M2050 as bus mice for the Apple IIc, Apple III and early Macintosh, "same as the 'Macintosh Mouse', only renamed". Community wiki, cited as a secondary source.
- ↑ Apple Computer, Lisa Level 1 Technical Procedures, #072-0085, Macintosh XL Illustrated Parts List, top assembly. Hosted as Apple Lisa Level 1 Technical Procedures Mar85.