Determining RC frequency...

[Ahmed El Sherbiny]

Hi all, excuse me for the question I feel is very stupid, but what is the formula to calculate external RC oscillator frequency ?

It's not mentioned in the datasheets...

Thanks in advance
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[R.J.Hamlett]

:=Hi all, excuse me for the question I feel is very stupid, but what is the formula to calculate external RC oscillator frequency ?
:=
:=It's not mentioned in the datasheets...
:=
:=Thanks in advance
It is the 'standard' capacitor RC charge formula. You can generate a pretty good 'rough guess' from the data sheet, based on the input 'low' voltage, input 'high' voltage, output 'low' voltage, and output 'high' voltage for the oscillator pins. These all depend on your supply voltage. Typical values, are 100pF, and 3.3K ohms, giving about 1.8MHz at normal room temperature.

Best Wishes
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