This section of the data sheet is provided to define the source of the clock or timer input into the processor as well as provide details of the clock modes or Multipliers available with this specific processor.  These settings will define the output CPU clock cycle. 

This section will define pin assignments and input sources required for the timer circuit of the processor.  In addition, a block diagram of the internal clock peripheral is defined to show the logic of the circuit and any additional elements that must be configured for the processor to operate. 

The table below is an example of the timer diagram.