20.7.2 Timer1 Gate Source Selection
The gate source for Timer1 is selected using the GSS
         bits. The polarity selection for the gate source is controlled by the GPOL
         bit. The following gate source are available:
   - Signal Measurement Timers
 - Configurable Logic Cells
 - Comparators
 - PWM
 - NCO
 - T1CLKIN
 
