Re: [NTLK] New accelerator idea. needs no crystal. Need Help.

From: Humphreys, David (URB) (david.humphreys_at_honeywell.com)
Date: Tue Jul 09 2002 - 10:29:23 EDT


-----Original Message-----
From: Andy Collins Sent: Tuesday, July 09, 2002 8:55 AM

Hi Folks,

I think I've come up with a different method of speeding up the MP2x00
without needing to change the crystal...

Oh dear! Don't do this! Quite apart from the exteme difficulty in isolating the pins, it won't work.

It is true that the SA110 uses a PLL to multiply the crystal frequency. The multiplication factor is determined by the
state of 4 pins on power up. If you change the level on these pins you will certainly change the core frequency. This is
fine but the same crystal runs the voyager asic. It will still be running at its' 'normal' speed. This chip has more to
do than just serial comms. There is a timing relationship between it and the SA-110 that is destroyed when you change
the configuration pins.
Changing the clock (crystal) frequency, on the other hand, keeps the system in 'lock-step'. From a system point of view,
changing the main clock is the best way.

Can the Newton be made to run at different speeds using the PLL muliplier pins?
Yes - but it requires a lot more than just switching them.

PCBman

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