The problem is the Chip does not run 4X internaly. A 10mhz crystal with HS and PLL does not run internaly at 40MHZ. ----- Original Message ----- From: "Byron A Jeff" To: Sent: Saturday, August 03, 2002 6:56 PM Subject: Re: [PIC]:Has any one ever got a PIC 18F244 chip to work at 40mhz > On Sat, Aug 03, 2002 at 05:46:16PM -0400, Michael Simpson wrote: > > The question is for the PLL option I am using a 10MHZ Resonator. IT works > > at 10MHZ with or with out the PLL option. > > > > As far as the crystals I have tried about 20 brands and types. I purchased > > about 10 each a few weeks ago so I could test. At the lower frequencies > > they all seem to work. fine. I have a few 10mhz crystals and again they > > work fine at XT or HS as 10MHZ. But in HS/PLL they are still running at > > 10MHZ. > > (sound of head scratching...) > > They are supposed to run at 10 Mhz. So what exactly is the problem? > > The PLL is internal and uses the 10 Mhz external signal to generate the 40 Mhz > clock internally. So there should be no change in the external appearance of > the external oscialltor. > > It's supposed to run at 10 Mhz. > > So I only have one question: When you enabled the HS/PLL mode did the chip > get 4 times faster than HS mode? > > Lastly did you read the errata page for the 18C chips. There are some issues > on oscillator speed based on whether the chip is industrial or extended. Take > a read if you get a chance... > > BAJ > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu