Quote Originally Posted by BrianT View Post
I have a need for the lowest possible power draw. I think I can get away with a 100 KHz crystal and still get around the main loop in time. The defines for PBP stop at 3.58 or 4 MHz. There are no LCDs or serial datacomms to worry about.
I realise the bootloader can't work and I want to use ICSP via a modified EPIC for code load and dump.
Questions.
Can I use PBP with DEFINE OSC 4 and then fudge any timing loops by calling up a delay of 1/40th of what is needed? (4 MHz/40 = 100 KHz). For example calling up PAUSEUS 25 would in fact become a pause of 1 mSec.
Are there any other hidden little gotchas I should be aware of?
BrianT
You can do exactly what you're talking about.
I do it on my '4620 on my OBD reader. The code I wrote has DEFINE OSC 10, which means it talks to my OBD chip at 9,600. If I turn on the 4xPLL when I program the chip, it'll talk to the OBD chip at 38,400, without changing any code.
And it works just fine, except that the pause loops get a little bit goofy and you have to program them all for worst case scenario.