What is CPU clock and system clock in PIC Microcontroller

[Kittu20]

Hi
Microcontroller operate on clock signals. clock source may be internal or external. I don't understand difference between system clock and CPU clock in PIC microcontroller.

Anyone help me to understand difference between both of them ?. What's fundamental concept of clock should be remember when programming microcontroller

 

[Harald Kapp]

There are more than these two clocks in a microcontroller. Read for example this page.

 

[Keonte45]

The system clock is needed to synchronize all components on the motherboard, which means they all do their work only if the clock is high; never when it's low. And because the clock speed is set above the longest time any signal needs to propagate through any circuit on the board, this system is preventing signals from arriving before other signals are ready and thus keeps everything safe and synchronized.

The CPU clock has the same purpose, but is only used on the chip itself. Because the CPU needs to perform more operations per time than the motherboard, the CPU clock is much higher. And because we don't want to have another oscillator (e.g. because they also would need to be synchronized), the CPU just takes the system clock and multiplies it by a number, which is either fixed or unlocked (in that case the user can change the multiplier in order to over- or underclock the CPU).

 

[Keonte45]

You could get more information on the differences online.

For instance:

Difference Between System Clock and CPU Clock

Difference Between System Clock and CPU Clock is that the processor relies on a small quartz crystal circuit to control the timing of all computer operations.

anydifferencebetween.com

 

[juliasmith]

System clock is the total clock speed of the whole system and cpu clock is the clock speed of its own.