pic 18:4550 is the internal osc accurate enough for USB?

[William At MyBlueRoom]

I know the 1% internal osc is fine for serial, but is it good enough for USB? On pics with usb harware built in?

 

[picasm]

No, The internal oscillator can't be used for usb on chips such as the 18f4550.

There is a section (2.3) in the manual which shows the choice of crystal oscillator frequencies and configuration settings to achieve low or full speed usb clock and the instruction clock frequency.

 

[Funny NYPD]

+/- 0.25% accuracy is required per full-speed USB specifications. There is very few PIC meet this standard.

The New PIC18F46J50 can only be used for low-speed USB with internal oscillator. It is better than nothing.