Calibration Word & Processor Speed

[cyberroth]

Hi,

I'm new to PICs & PicBasic Pro, but not new to microcontrollers in general. Atmel, ST9, Picaxe,8051

I was recently given a (legal) copy of PBP 2.46,.Microcode Studio, MPLAB 7.11 and and (2) ICD2 Programmers, along with a box full of PIC16F684 and 12F688 PICs. I am slowly muddling my way through the toolchain and getting fimilar with the little idiosyncracies.

After building a programming board for use with the ICD2 I got an LED to blink after a couple of hours of trial an error. Not bad. It took me 3 days with an ST9B ....

Thanks to information posted in this forum, I was able to quickly figure out how to change/modify the configuration word bits, as I want to try using using a 20Mhz crystal instead of the internal RC oscillator, However ......

I have a question about the factory loaded "calibration word" loaded at 2009h.

How can this be changed or reloaded if, for example, it gets overwritten? I have searched and found no information on how to do this with an ICD2. To the best of my limited knowledge, the ICD2 does not have a stand alone programming app, and its "operating system" is programmed to leave this data alone.

Also, the PIC 16F684 has a default 8Mhz internal clock, yet PBP by default slows it down to 4Mhz. ...Why is this?. Does 8Mhz not work well or cause some PBP features to misbehave?

I changed the clock to 8Mhz with "DEFINE OSC 8" but see no obvious improvement in performance. How can I easily tell if the oscillator speed actually changed ? Is there a simple way to test the performance with PBP or MPLAB ?

Thanks in advance.

cyberroth