Two questions - 18F87J50

[spcw1234]

1. I'm using a 20 MHz crystal that has 4 pins, 2 ground and the 2 osc. Does it matter where I connect the two osc pins? In other words, does it matter if I connect osc1 where osc2 is supposed to go.......if that actually is supposed to happen?

The osc can be put in either way. Not familiar with VDDcore.

[Dave]

Chris, what voltage level is the supporting electronics going to run at? If it is 5 volts then I would enable the internal VCORE regulator and run the processor at 5 volts. If you want to conserve power and the support electonics can tolerate 3 volts to operate then by all means disable the internal regulator and provide your own 3 volt supply. I am currently developing a system that uses an 18F67K22 which has this exact feature. I have chosen to enable the internal regulator and drive all the supporting electronics at 5 volts. It works just fine.

[rmteo]

Chris, what voltage level is the supporting electronics going to run at? If it is 5 volts then I would enable the internal VCORE regulator and run the processor at 5 volts.

Absolute maximum voltage for the PIC18F87J50 is 4.0V (recommended is 3.6v) - Section 28.0 of the data sheet.

NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.