Re: [NTLK] PCMCIA cards and clock signals and accelerated Newts

From: Paul Guyot (pguyot_at_kallisys.net)
Date: Sat Apr 13 2002 - 03:57:51 EDT


Date: Tue, 9 Apr 2002 21:34:50 -0500
From: Jim Witte <jswitte_at_bloomington.in.us>

> > I successfully used the 3c589d with my accellerated MP2100 and
> > accellerated eMate.
>
> Won't any PCMCIA card successfully work with the accelerated Newts,
>since the PCMCIA's clock signal is not generated by the main crystal?

There is no PCMCIA clock signal.
Let's look at ATA Support's driver. The doc says: write this, wait
for n, then read this and so on. To do so, I ask the system to wait
for n. If it was used in an accelerated Newton, I would wait less and
the ATA card might not reply properly. (note that since the
beginning, the delays I've used are computed to work in both
accelerated 2.1 Newtons and unaccelerated 2.x Newtons, they don't
work in accelerated MP1x0, though).

>Paul, for the accelerated Newts, would it be possible to patch (by
>extension, not neccessarily by system patch) the global time functions
>to "run slower"?

You can do several things:
a/ patch the sounds so they play slower. Doesn't work with system
sounds, but does with recorded sounds. This was suggested by Michael
Schaefer. We might be able to do the same with various other things.
b/ patch various places in the system so things are executed slower.
May be heavy. Requires the system patch
c/ patch the functions that makes you wait for a while so they wait
longer. Requires a system patch. Would be the best solution.

>Of course, this would mean the clock would then get
>screwed up if you ran the Newt at "normal" speed, unless the extension
>could detect it and compensate (rather unlikely to the percision you'd
>need to keep it in sync).

Well, I don't think keeping sync is the problem here. There is no
clock but functions telling you the time since last reboot, and these
don't have a big precision and aren't involved in most operations
including card operations. When the Newton is blocked by the
low-level debugger, this value isn't incremented and everything is
alright.
Functions giving you the time rely on a clock chip and it beats at
the same speed whether the newton is accelerated or not.

Paul

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