Subject: Re: Oh, well. / ADB controllers
To: MacBSD General Mailing List <>
From: kr <>
List: macbsd-general
Date: 07/17/1994 16:19:48
At 13:30 7/13/94 -0700, Brad "ADB Guy" Grantham wrote:
>with Powerbooks ad Duos that we may or may not be able to correct some day:
>        1) different ADB implementation than the current MacBSD (possibly
>        the same as the IIsi, IIvx, and other desktop machines)

Why don't we collect some data to determine the scope of the diversity of
ADB implementations and the scope of the problem ? The most
straight-forward and low-tech approach is to just open all these boxes and
write down the exact IC number of the controller chip. Every real hacker,
of course, must be delighted to take apart his machines to watch the
gleaming circuitry, and this way we can also collect the necessary data.
Certainly the desktop machines are easy to open, as many provide expansion
slots anyway. There might be more of a problem with Powerbooks (I never had
one in my hands). Maybe with those, actual screws have to be removed, which
are maybe hiding below the rubber feet, or all these other tricks that
manufacturers play to keep their customers out of the system and
uninformed. :-)

In my IIsi, the RTC and ADB controller chip is one of these 68HC05, a
dual-in-line surface mount component with 28 pins. Besides the nice
Motorola logo, it says:

(c) APPLE 1990

The top number with the S is probably the significant number we should
watch, which describes the chip's identity.
As far as I know, this chip is also involved in the (crude) power
management of the IIsi and switches the main power supply on and off. It is
very likely (in my personal but uninformed opinion), that the same chip (or
a derivative thereof) is also involved in the more extensive power
management in the Powerbooks. Hopefully, the software interface is similar.
Brad mentioned that maybe the ADB is powered down also by the shutdown
manager. It might well be that the ADB is somehow deactivated, but if a
similar chip to the above is responsible for this, that chip itself will
always remain under power, as it also hosts the RTC. It can run off the Li
battery (is there one in Powerbooks ?).

Markus Krummenacker