Re: Relation of crystal and CPU



On Feb 15, 3:31 pm, "jackycheung" <jackymaill...@xxxxxxxxx> wrote:

I've 2 stupid questions related to crytstal

A mastery of understatement. You need to learn to read datasheets.

From my understanding, crystal is used to generate CLK for MCU. But what

Maybe.

is the relationship between crystal and PLL? And what can be measured in

Maybe nothing. Does your micro have a PLL? Does it have a DCO? Are you
using either, or are you using the crystal as a raw clock source?

the crystal pin when the MCU is in reset or run state?

There is no way of answering that generically.

Also I would like to know how to read crystal value marked on the crystal

Crystals are generally marked with characters from the Roman alphabet
<http://en.wikipedia.org/wiki/Roman_alphabet> and digits from the
Arabic numeral set <http://en.wikipedia.org/wiki/Arabic_numerals>. In
rarer cases you might find letters from the Cyrillic alphabet <http://
en.wikipedia.org/wiki/Cyrillic_alphabet>.

Those are the generalities; of course for specifics you would refer to
the crystal manufacturer's datasheet, would you not?
.