Hi Folks,
I think I've come up with a different method of speeding up the MP2x00
without needing to change the crystal.
I've been pondering speeding my Newt up since discovering Stephanie's web
page but the things that put me off were...
1) I'd need to bring the speed down to download packages and backup (I only
have serial coms).
2) Running the wires around radiating at the clock frequency.
3) It doesn't seem right to speed up everything, memory timings, LCD
refresh rates etc.
I asked a hardware savvy friend of mine if it was possible to use some kind
of chip to switch frequency. That way this chip could be near the processor
and the wire to the physical switch would only be handling DC. At least
that would cross of one of my objections.
The upshot of that was that it could easily be arrange but he asked the
question why didn't I just change the multiplier? Why? because I didn't
know there was one :-). It seems the multiplier takes the crystal frequency
given to the StrongArm microprocessor and multiplies it by a set amount to
give the internal frequency that the SA110 runs at. It turns out that there
are four pins on the SA110 that set the multiplier inside the processor.
The great advantage is that, if my hunch is right, only the core of the
chip will run fast. The Voyager and therefor the serial coms etc will run
at normal speed. The memory timing will remain unchanged. There is a
question mark of sound (chipmunk or not) but apart from that I recon the
Newt won't need to be switched to the normal frequency again.
This is where I'm at...
I've Downloaded the data sheets and worked out what's what.
I've lifted the for core clock multiplier pins from the circuit board
(_VERY_ tricky don't try this! very hard!).
Fitted a small 4 pole tri-state DIL switch (this will be removed when it's
all working).
Now I can try trying the pins controlling the multiplier high or low as I
wish. switch settings and check the results.
Now here's the problem.
It doesn't work!! I can change the levels on the multiplier pins but it
doesn't seem to work properly. It either works at the same speed or hangs.
Has anyone else looked into this? Any hints and tips from the hardware
gurus greatly appreciated.
Thanks.
Andy.
WARNING... This is proving tricky. It might turn out to be a brilliant
idea. However, I might wreck my Newton. Don't blame me if you try this and
wreck yours!
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