[TI-H] Re: 89 hw versions
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[TI-H] Re: 89 hw versions
>At 01:23 2001-04-11, you wrote:
> >I don't think so, I believe just that the clock is sped up from the HW
> >1....and the processors are tested to work at this frequency instead
> >(12Mhz).
another thing about this. The actual processor in even the hw1, works well
up to about 30MHz (I think it is specified (tested) for somewhere in the
20MHz range)
The reason you can't overclock it this much though, is that signals to the
memory becomes to short.
here is a clip from johan borgs faq on overclocking:
----8<----
why only ~15MHz?
the uP-chip can run at up to ~30MHz or so, but the RAM cant.
the time byte-CS is active when a byte is written is much shorter
than the time for read or word-write, and when the frequency
is incresed, that time soon becomes too short.
the OS actually boots with quite high frequencys, because most writes
are word-writes, however doing anything will fail, and any text
printed will be more or less wrong.
----8<----
There is also a suggestion of a way to fix this, that as far as I know, is
not tested yet.
This applies to hw1 mainly though, since that was the only version
available when the tests where performed...
Does anyone _know_ how it is with hw2? (no guesses please, I can guess
myself. like, have performed tests on this on an actual calc)
///Olle
References: