Path: utzoo!attcan!uunet!wuarchive!usc!elroy.jpl.nasa.gov!ames!aplvax!ames!rex!samsung!cs.utexas.edu!news-server.csri.toronto.edu!qucdn!leek
From: LEEK@QUCDN.QueensU.CA
Newsgroups: comp.sys.amiga.tech
Subject: Re: games & multitasking
Message-ID: <90160.145128LEEK@QUCDN.BITNET>
Date: 9 Jun 90 18:51:28 GMT
References: <1696@lpami.wimsey.bc.ca> <90159.131952LEEK@QUCDN.BITNET> <21524@estelle.udel.EDU>
Organization: Queen's University at Kingston
Lines: 52

In article <21524@estelle.udel.EDU>, new@udel.EDU (Darren New) says:
>
>In article <90159.131952LEEK@QUCDN.BITNET> LEEK@QUCDN.QueensU.CA writes:
>>The serial port is probably the only "safe" port
>>to plug & unplug devices when the machine is on

I said that because the output chip 1488 have some form of current
limiting while the input chip 1489 can handle +/- 30V inputs.  For
most conditions, they are almost indestructive.  (I've them blowing
up on a 68HC11 Evaluation Board - but that shouldn't happen in the Amiga)

>
>I thought the keyboard at least was also "safe".  I remember reading
>about all the nifty stuff to make sure that the amiga does not get
>spurious (sp?) characters when the keyboard is plugged in out pulled
>out.

The keyboard connector is safe in the sense that it is very unlikely to
get junk characters when you connect/disconnect it.  Electrically, it is
unsafe.  The keyboard plug goes directly into 8520 PIA chip with no
protection circuits.  I remember reading the BIX stuff in the early days
about people with non-Commodore keyboard cable burning chip(s) in their
keyboards.  This happens because they short circuited the pins on the
A1000 keyboard plug.  The only improvement in the keyboard interface in the
B2000 seems to be the 0.5A fuse and a different plug.  The fuse is there to
limit the damage.  I don't know whether or not it is good enough to prevent
damages for/from  non-Commodore approved devices.

>
>Also, what about the game ports (aka mouse ports)?  Can I do damage to
>the Amiga by plugging or unplugging unpowered devices (mice, sticks,...)
>to these ports while the power is on?

Let's see.  The +5V source from the game port has some current limiting
on A1000, A500 (can't tell from A2000 schematic), the POT0X, POT0Y, POT1X,
POT1Y goes directly into Paula again without protection.  If the
device you plug in is a joystick/mouse, I think they are probably safe.  I
can't tell what would happen for non-Commodore approved devices such as a
dongle.

Last time I check, Paula was about $60 and 8520 was about $15 a piece.  Both
of them are not user installable.  The replacement labour cost might range from
$25 to $50.  That's the reason why I say I would sue any copy protection that
damage my machine. (about 3 times already).

>                         -- Darren
   //
[\X/] for multitasking games (Amiga juggling tiny BOING! balls)
      for OS environment friendly products (Mult-colour check mark)

[ X ] for dongle protection, disk base (grind-grind) protection, games that
      takes over the machine (Wipe-outs)