[TI-H] TI-89 HW2 overclocking
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[TI-H] TI-89 HW2 overclocking
Hi, I've found several pages on TI-89 overclocking. This one in particular
has a table of values of capacitance vs. MHz:
http://translate.google.com/translate?hl=en&sl=fr&u=http://planete89.free.fr/hardware.php3&prev=/search%3Fq%3Dti-
89%2Boverclock%2Bc10%26num%3D50%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3Dutf-
8%26sa%3DG
The original in French is:
http://planete89.free.fr/hardware.php3
They are replacing C10, so they're overclocking a HW1 calculator.
Here is the table: (monospaced)
Capacity Time Frequency
2.7pF do not go do not go
3.3pF (some bugs) - 7s 22.9MHz
5.6pF (of small the bugs) - 7.5s 21.3MHz
10pF 8s 20MHz
12pF 9s 17.8MHz
22pF 11s 14.5MHz
normal 15s 10.7MHz
100pF 27s 5.9MHz
120pF 30s 5.3MHz
390pF 205s 0.8MHz
where "Time" is the time to complete the benchmark of graphing z=sin(x)
+cos(y) and Frequency is
measured by TiBench 1.0.
I'm wondering about the relevancy of this information to overclocking an
HW2 calc (except replacing
C4 instead of C10). My TI-89 does the z=sin(x)+cos(y) graph in 11s and
TiBench 1.5 says 12.6MHz,
implying that this HW1 data can't be directly compared to a HW2 calculator.
So, my question is: have enough people overclocked their HW2 TI-89 on this
mailing list to construct
this same data? (obviously differences in battery voltage will cause some
variance in the statistics)
Also, I haven't seen any other pages that recommend using smaller than a
22pF cap.
(And I've got some ideas for getting to the "do not go" speeds involving
some microsoldery and some
55ns SRAM -- anyone know how fast the mc68sec000pb16 can be clock-chipped
with fast RAM? and if I'm
not mistaken, according to Motorola's datasheet, that's a 16MHz chip, as
they don't make a 12MHz
version.)
(Oh, and one last postscript to the inevitable "but why would you want to
overclock a calculator"
questions: ever tried solving a nasty definite integral from 0 to x = some
value, for x? or taken
a leslie matrix to around the 40th or 50th power? or graphing? hasn't TI
heard of an optimizing C
compiler? </rant>)
--
B.A. Baracus
The A-Team
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