[TI-H] Re: TI-89 HW2 overclocking


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[TI-H] Re: TI-89 HW2 overclocking



Invalid Fake HTML syntax.  Please use tag <rant> before ranting and 
closing with </rant>.

Anyway, there may be other factors in HW2 calcs that may make it faster. 
 Are the RAM, ROM chips the same, and how about all other chips, 
capacitors, etc.?

B.A. Baracus wrote:

> 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>)
>





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