If the frequency of the crystal oscillator is 20 MHz on a PIC16F877a, the frequency of the signal on OSC1/CLKIN would be?
To determine the frequency of the signal on OSC1/CLKIN, we need to understand the clocking circuit of the PIC16F877a microcontroller.
The PIC16F877a has an internal oscillator circuit that requires an external crystal or resonator connected to OSC1 and OSC2 pins to provide the clock signal. The crystal oscillator determines the frequency at which the microcontroller operates.
Typically, the PIC16F877a microcontroller uses a 4 MHz crystal oscillator by default. However, the frequency can be changed by configuring the oscillator settings.
Now, in your case, if the frequency of the crystal oscillator is 20 MHz, then the frequency of the signal on OSC1/CLKIN would also be 20 MHz, assuming no additional prescalers or dividers are used.
To verify the frequency of the signal on OSC1/CLKIN, you can refer to the datasheet or documentation of the PIC16F877a microcontroller. It will provide the detailed information about the clock configuration and the relationship between the crystal frequency and the oscillator output frequency.