Clock for 18F2550

nikin78 · Joined: 20 Sep 2007 Posts: 11

I have seen various sample code for the 18F2550. it looks to me that a 20MHz external clock can give you a 48MHz clock with the following code

#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN,NOBROWNOUT,MCLR

if this correct please help me understand the math or explain the last paragraph in 2.2.4 of the PIC datasheet for the 18F2550/4550. it doesn't make sense to me.

I also noticed the same code as above is being used in the sample code for the USB development kit CCS provides. So I know it is correct but I dont know why.

libor · Joined: 14 Dec 2004 Posts: 288 Location: Hungary

Ttelmah makes a good explanation on this issue in this thread, also look for the graphic diagram on the website linked at in the last post.