To connect the SR latch output on C2OUT to the Timer1 input pin T1CKI, it is possible to use this square wave as the Timer1 clock source. Configuring the TMR1 register to increment on every positive edge of the square wave counts the number of clock pulses. However, this isn’t enough to determine the frequency of the square wave. To do this it is necessary to have a fixed period clock source to gate the 16-bit TMR1 value.