Internal oscillator

[Olufola]

hi all,
I want to use the internal clock of pic18f4520 for the first time. I have always used external crystal oscillators. Do I stand to suffer any disadvantage. In what ways is the internal oscillator inferior to the crystal oscillators.

[Ttelmah]

Accuracy.
Typically at least three orders of magnitude worse.
This is why on things like the USB chips, the internal oscillator cannot be used for USB.
Generally, for most normal tasks, the internal oscillator on modern chips is 'good enough', for things like standard serial, _over a limited temperature range_. 'Room temperature' type environments. However anything wider than this, needs you either to compensate for temperature (measuring it, and adjusting the oscillator tuning value), or use an external source.

Best Wishes