What is a PCA (Programmable Counter Array) in the 8051 Microcontroller

Hi everyone.

I'm studying for the finals in my 8051 Microcontroller course and i don't understand what is the PCA (Programmable Counter Array) in the 8051 and what it is used for.

Can anyone please explain to me what is a PCA, what it is used for and how do we use it?

Thanks,
Reshef