PIC18F2550 Newbie

[rhino]

Try DEFINE capitalized.

[skimask]

Try DEFINE capitalized.

GOOD call!
I was going for the misconfigured PLL myself...but yours is much better...

[JeffnDana]

Actually, in my code DEFINE is capitalized. Sorry for that, not sure why it isn't capitalized in my post.

[rhino]

hmmm.... I'm stumped. Might want to look into what Skimask says about the PLL. Check out this LINK. You may have to tell us your PBP version, IDE, MPASM version, programmer, social security #, mother's maiden name, etc.

[peterdeco1]

Hello. I had similar timing issues with a 18F2510. In my case, the timing was slower than it should be with a 4MHZ resonator. Within MPLAB I changed the watchdog postscaler from 1:128 (DEFAULT) TO 1:8. This seemed to correct the problem. I noticed the 2550 defaults to 1: 32768. Maybe you can try this route

[JeffnDana]

I got it working thanks to all of you. I'm using MicroCode studio and changed the configuration settings from the Compile and Program dialog. While changing the watchdog postscaler setting I noticed that the Oscillator mode was set to HSPLL. When I set this to HS the timing was correct. According to the datasheet there is a postscaler adjustment for the PLL setting (1/2, 1/3, etc) so I assume I would change that if the mode were HSPLL. If I understand it correctly, I would want to use HSPLL when using the USB functionality.

Thanks again,
Jeff

[skimask]

If I understand it correctly, I would want to use HSPLL when using the USB functionality.
Thanks again,
Jeff

The HSPLL can be used anytime, whether using USB or not. Use the HSPLL, and you can get 48Mhz internal at the PIC, while only having to design for a 12Mhz crystal/oscillator. Makes circuit design just that much easier than trying to get a 48Mhz crystal to work on a sloppy design.

[JeffnDana]

Thanks for the info skimask, that's good to know.