18F4550 oscillator config

hgboy · Post by **hgboy** » Wed Feb 04, 2009 9:40 pm

I plan on using an 18f4550 to run a glcd, and would like to have it running as fast as possible to get decent refresh rates. As far as I can tell, the maximum frequency for the 18f4550 is 48MHz. How would I set this up in my code, and what type of hardware configuration would I need? I am having a little trouble figuring this out from the datasheet.

Mikeclx · Post by **Mikeclx** » Mon Feb 09, 2009 6:07 am

this is my config

Device = 18F4550
Clock = 48

Config
PLLDIV = 5,
CPUDIV = OSC1_PLL2,
USBDIV = 2,
FOSC = HSPLL_HS,
VREGEN = ON,
MCLRE = off

I use Resonators with built in caps rather than crystal... less board space... never had an issue with them they just work..

Connect the 20mhz resonator accross the OSC1 and OSC2 pins and to ground