Date   : Tue, 14 Aug 2007 19:00:21 +0100
From   : dl.harper@... (David Harper)
Subject: Depraz mice + Master 512

Jules Richardson wrote:

> OK... so, does anyone know what pinout the M512 is expecting? I get no
> response from the mouse that I just tried (it's possible that it's broken 
> of
> course) - GEM just starts up OK but the mouse pointer never moves.
>
> The Depraz User Port connector pinout seems to be:
>
>   port pin   function
>     1        +5V
>     6 (PB0)  Middle button
>     8 (PB1)  Left button
>    10 (PB2)  Right button
>    14 (PB4)  Y1
>    16 (PB5)  Y2
>    18 (PB6)  X1
>    19        GND
>    20 (PB7)  X2
>
> ... anyone know if that matches the mouse pinout for whatever mouse 
> actually
> came with the M512?

This does not match the standard, I'm afraid. Standard mouse pinouts are:

    pin               function
     1                   5V
     2 (CB1)        X Ref
     4 (CB2)        Y Ref
     5                   Gnd
     6 (PB0)         X Sec
   10 (PB2)         Y Sec
   16 (PB5)         Sw3
   18 (PB6)         Sw2
   20 (PB7)         Sw1

This is for the AMX / Quest mouse (which work perfectly well with the M512) 
as well as the supplied Acorn mouse (which has no middle button).

It looks like you have some rewiring to do!

Once the hardware is correct, you do not need to do anything to get the 
supplied version of GEM to use the mouse. For a mouse driver that will work 
with GEM Vn. 3 (or other mouse-enabled programs that will run on the 512) 
see:
    http://www.cowsarenotpurple.co.uk/bbccomputer/master512/software.html

David Harper