Re: [iPAQ] cpu speed

On Fri, Oct 13, 2000 at 09:04:44AM -0400, Noel J. Bergman wrote:
> According to the Jimmy Software folks, they have clocked it all the way to
> the max with excellent results. The only problem at the max was with
> ActiveSync.
>
> See http://www.jimmysoftware.com/ipaqoverclock.htm for more detailed
> commentary on the effect of overclocking, and how to trim devices.

They are most certainly not at the maximum speed: the maximum speed
with a 3.6864 MHz crystal (as used by the iPaq) is 369 MHz, but that's
pure theoretically. With normal core voltage, you can reach 236 MHz at
maximum, but if you increase the core voltage, you can reach 280 Mhz.
Increasing the core voltage is not without risk, we actually blew up a
couple of CPUs by supplying over 1.96 V.

I don't know what ActiveSync is (I don't do Windows), but I suppose it
uses the serial port. The URL states that the serial port clock is
affected by the core clock, but that's simply not true (see section
11.11.4.1 in the SA1110 manual). Problems with the serial ports are the
first indicator that the choosen clock speed is already too fast; if
you increase the clock speed even further, the machine will lock-up
completely.

Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
Phone: +31-15-2783635  Fax: +31-15-2781843  Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/