Is 2.5 V a suitable voltage for the X1 pin of the X1 oscillator?
Q1 Although 3.3 V is supplied as the power supply of the 78K0R/Kx3 and a ceramic resonator is connected to the X1/X2 pins for clock oscillation, measurement of the voltage of the X1 pin results in only 2.5 V. Is this OK? A1 In the 78K0R/Kx3, since the power generated by the internal regulator is supplied to the oscillator, the amplitude of the oscillator corresponds to the voltage of the internal regulator. So yes, this is OK.