[TI-H] Re: TI-83P SE hardware, looking for thoughts
[Prev][Next][Index][Thread]
[TI-H] Re: TI-83P SE hardware, looking for thoughts
Well, I created some software to measure the CPU clock frequency on the SE
using the timers. I tested with batteries at 5.018 and 5.853 volts. The
numbers were very close. However, I had a slight nagging feeling on that,
and decided to test a regular 83P as well. Again here the numbers were very
close. So, apparently we can't draw much from this, other than perhaps the
same "voltage regulator" that keeps the LCD at a constant contrast
regardless of battery voltage works for the CPU as well. Either that or I
messed up my tests, but I'm hoping it was the former :)
Here's the data (I ran multiple tests on each setup, I'm only including the
averages here though)
SE 5.883 volts - 5.990 MHZ
SE 5.018 volts - 5.987 MHZ
(Due to laziness, I didn't actually measure CPU speed on the 83P, I just
measured a certain number of fixed-lengths "loops", but it doesn't matter as
it's consistent between trials)
83P 5.883 volts - 47199
83P 5.018 volts - 47205
-Dan
----- Original Message -----
From: "Alejandro Paz" <psys@cotelco.com.ar>
To: <ti-hardware@lists.ticalc.org>
Sent: Thursday, July 26, 2001 8:56 PM
Subject: [TI-H] Re: TI-83P SE hardware, looking for thoughts
>
> Hi,
>
> To find out if the main clock is wired to the xtal or to a RC oscillator
> you have to lower the VBatt (using +5V instead of +5V or so) and measure
> the main clock (directly or through the timer). If the main clock is
> wired to the crystal the freq will not vary, on the other hand if its
> varies an RC oscillator is used.
>
>
>
References: