Amstrad PC1640HD20

From: Lawrence Walker <>
Date: Wed Jan 10 21:34:33 2001

> > The connection on the side for the mouse is a DE-9. Are you
> Same on the PC2086
> > saying it wouldn't function without a K-B. If so, is the mouse also
> The movement will work, the buttons won't. The quadrature signals from
> the movement sensors go to one of the ASICs on the motherboard, the
> button signals go to the keyboard.
> > proprietary ? A 3 button mouse came with this 1640HD20 and I
> It's a quadrature output mouse, like an ST mouse, an Amiga mouse, PERQ
> 3a mouse, PC bus mouse, original (pre ADB) Mac mouse and so on. The
> connector pinout is specific to the Amstrad.
> Does that make it 'proprietry'? You can't plug in a normal PC serial
> mouse (the mouse port is not a serial port, or a PS/2 mouse port). And
> you'd have to rewire the connector [1] to use another quadrature mouse
> on the Amstrad. But it is the standard TTL level quadrature signals as
> used on many classic computers.
> [1] This is something that never worries me....
> > just tossed it in my mouse box among the multitude of others
> > figuring it was standard. Was this likely not the original mouse ?
> If it's 3 button then it's not the original mouse. Does it have any
> maker's name on it? Have you openned it up to see if it appears to be
> quadrature output or if it has an internal microcontroller (and thus
> is some kind of serial mouse). How many wires are used in the
> interface cable?
 The mouse is labelled Memorex. I haven't taken it apart yet since
in any case I don't yet have the K-B to see whether it is functioning
or not.

> AFAIK you can use a normal serial mouse with the Amstrad (if you load
> the right drivers) but you plug such a mouse into the serial port and
> not into the mouse connector.
 Perhaps that's how it was connected. But I see that the serial
socket is a male 25pin and generally when someone tosses these
they just leave the adapter on the puter or on the device. It could be
incidental that the mouse just happened to be tossed at the same

>> My ST mouses (mice ?) has a simple switch to change it
> ^^^^^^^
> meeces ?
> > to an Amiga mouse. I also have a Kraft joystick with DE9 and
> Yes, the real difference between Atari ST and amiga mice is the wiring
> of the connector. Rearranging the wires (which is what the switch
> does) will let the same mouse work on both machines).
> A few years ago, Maplin (a UK hobbyist electronic component shop) sold
> replacement mice for the ST and Amiga. One was 2 button, the other was
> 3 button. I used them as replacement mice on all sorts of machines
> (the Amstrad PC2086, the Mac+, Acorn Archimedes, etc) just by
> replacing the connector (and wiring it appropriately). Alas you can no
> longer get these very useful mice, just the much less useful PC serial
> type, which work on almost no machines that I have.
 I have always snatched up any preADB mice I came across and
so have about a 1/2 doz. of these. Ditto for strange K-Bs which
came in handy for a bare Tandy 1000 I acquired. I had 2 of these
hard to find beasts. I have an Atari with an RJ11 connector waiting
for whatever it originally came with ( a TTxx ?)

> One day I must program a microcontroller to talk to a PC serial mouse
> and give out quadrature signals on the other side so I can use a PC
> serial mouse with many of my classic computers.
> > DB15 connectors and a switch to change between Apple IIe and
> > PC. There was a box from Practical Peripherals called Mouse-
> Actually, the PC joystick port and the Apple ][ (//e, etc) joystick
> port are electrically very similar. Both are based on the 558 chip (==
> quad 555, all 4 timers hardwired to monostable mode, approximately),
> and thus both need variable resistors between the joystick inputs and
> Vcc. So it's not suprising that the same joystick could work with
> both.
> Some other machines have true A-to-D converters for the joystick ports
> and want to see a changing voltage, not a changing resistance, at the
> joystick input. Of the top of my head, the Vectrex, Tandy CoCo (and

 Ahh so that explain the desirability of the Co-Co joysticks which
otherwise are pretty flimsy and not especially well designed.

> Dragon), some models of Tandy 1000, Tatung Einstein, BBC micro, etc
> are like this. Converting a variable-resistor joystick (like a PC
> joystick) to work with one of these machines is a little more 'fun',
> especially if only 2 terminals of the variable resistor in the
> joystick are available (so it can't be rewired as a potentiometer to
> give a varying voltage). A few op-amps will solve the problem, though.
> -tony
 In looking at the rear of the Amstrad I also noticed it has a bank of
10 switches labelled "display selector". This is curious since the
display is integral to it. What would you "sellect" with this ?

ciao larry

Reply to:
Received on Wed Jan 10 2001 - 21:34:33 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:33:47 BST