BasicMicro - Forums

Hello forums (Acidtech),
I Mr. nooby grazza am wondering if i can get my nano 28X to run at faster speeds than the 20MHz that it runs with the typical resonator. I feel very doubtful in this request by I am curious to see what to do.
Thanks heaps

Yes, as the processor is preprogrammed to use high speed resonators and crystals. That is, the circuitry is in place to handle those parts. There is a useful upper limit, however, and Microchip specs the highest SUPPORTED clock as 20 MHz for the part. But you can probably bump that a bit to 22- or 24MHz. If the processor can handle these higher speeds properly, this leads to two things:
1. Higher clock speeds means higher chip temperatures, though probably not to the point of part damage. I can't say what the high limit is for this situation, you'll have to experimrnt some.
2. All the timings are shot. Your programs won't run properly for anything but the simplest commands, like inputing and outputting levels to and from the pins. Serial rates will be all wrong, measurement functions will give wrong values, and even ADIN may not work reliably.

There are ways around most of problems. Unfortunately, the solutions call for extra coding to correct misstimings, and all the extra processor work largely cancels out the faster clock.
Take care.

_________________
kenjj
http://blog.basicmicro.com/
http://kjennejohn.wordpress.com/

Thanks a lot for your help kenji you have helped me out heaps

BTW, a third effect is: You can't program the part because the serial rate is off! You'd have to have interchangeable resonators in your design. Put the 20MHz resonator in to program, swap it out for the faster resonator when running the program. Ehhh!

_________________
kenjj
http://blog.basicmicro.com/
http://kjennejohn.wordpress.com/