In neither of the two threads you started, did you comment at all about your needs for a clock source type, resonator, crystal, or internal. Even though, many people elaborated on that.
You may not need any resonator or crystal at all.
In neither of the two threads you started, did you comment at all about your needs for a clock source type, resonator, crystal, or internal. Even though, many people elaborated on that.
You may not need any resonator or crystal at all.
That sounds correct. Did you have a question or observation about it? Did you compare the two instances and reach any conclusion about whether they are compatible?
My post was a reply to reply #26. Are you able to properly translate my replies into your first language?
So.... ?
Also, unless I missed it, you never posted any link to the specifications... so I can only imagine the circuit you describe.
What is your electronics skill/experience level?
You seem welded to the idea of copying the resonator circuit. So what is the actual problem with that? Just do it.
You didn't post the link. Likely, the capacitors are internal. This was already mentioned many posts ago.
What schematic? What xtal?
LINKS PLEASE
For me, forever. I have no such time to waste. Good luck with your project.
I suggest that if you return with more questions, that you carefully read the forum posting guideline documents first.
I will not see any of your further replies.
Many clones have a theoretically superior quartz crystal. Who knows for sure if they're "good" crystals, or whether they've had any attention paid to the proper load caps
They tend to be very low-priced, so component quality is somewhat in doubt.
You could also connect an external oscillator with temperature-controlled oven, calibrated to absurd levels of accuracy, if you really wanted to.
Okay, point taken. But I really meant superior frequency stability, which would be the case regardless of part source or capacitor values...
OP is sourcing their own parts, they can easily look for ISO9001 manufacturing standards, or whatever if they want.
Now, if you ask me, can the OP find the right capacitor values, well that is hard to tell from this thread. ![]()
I repeatedly tried to dig out some details about how the clock could behave - considering that the internal clock might work for many applications. But I never got any response... that would have the fewest components, of course, and render all the clock engineering moot as well.
It's not clear to me that ANYONE can pick the "right" capacitors.
I mean, the theory is published, but there seems to be a lot of reliance on things that are significantly difficult to measure (pin, pcb, and lead capacitance, for instance. Down in the single-digit picofarards.) Most designs seem to be more in the "well, it oscillates, and the time returned by millis() (or equiv) isn't horribly wrong, so I guess that's close enough!"
I happened to be looking at that today; I have a board design that may benefit from a gate based oscillator. The rule of thumb to get very close, is each capacitor value should be twice the xtal capacitance, minus stray board capacitance (which of course is usually a guess).
That must be in the single or few pF range, which is about 20 times less than the capacitances involved, so...
If the target of the calculations is fixed frequency accuracy, a variable capacitor is a must. That is a few steps beyond getting it to oscillate reliably.
Also, somewhere along the line people started to need reminding about keeping the traces short, not running signals next to it, and shielding the area around it as much as possible with effective ground planes.
When I went to school, a classmate's audio amplifier assignment oscillated strongly, bleeding RF into every setup in the lab. Then we had an RF oscillator assignment and he couldn't make that oscillate.
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