Fewer parts, lower cost, less chance of solder problems, less space required on PCB, saving the planet, the list goes on.I've been using external oscillatorsmainly 'cause I bought a bag and enough capacitors, but that might change with USB.
The datasheet is your friend:
http://ww1.microchip.com/downloads/e...Doc/39632e.pdf
Page 32, section 2-3:
When these devices are used for USB connectivity,
they must have either a 6 MHz or 48 MHz clock for
USB operation, depending on whether Low-Speed or
Full-Speed mode is being used. This may require some
forethought in selecting an oscillator frequency and
programming the device.
The full range of possible oscillator configurations
compatible with USB operation is shown in Table 2-3.
I just pulled out a 18F4550 about 10 minutes ago to get back into USB programming. We share the same datasheet, but I can't comment on config yet, I have to search the forum for examples first. (Here's an interesting thread to start with)
http://www.picbasic.co.uk/forum/show...18f4550+config
Robert
EDIT: But then it says this under the table:
Since several of my PCs don't have USB 2.0, I'll be targetting low speed.Legend: All clock frequencies, except 24 MHz, are exclusively associated with full-speed USB operation (USB clock of 48 MHz).
Bold is used to highlight clock selections that are compatible with low-speed USB operation (system clock of 24 MHz,
USB clock of 6 MHz).
Oh yes, don't forget that new PCs have USB 3.0, you'll have to look at an expert here to know how to handle that.
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