3.2 Timer1 Mode for Compare
Timer1 must be operating synchronously to the system clock for the
CCP module to use the compare feature. When Timer1 uses the internal instruction clock
(FOSC/4) as its clock source, clock synchronization is handled by module
hardware automatically. When Timer1 uses an external clock source, the Timer External Clock
Input Synchronization Control (SYNC) bit must be clear (SYNC = 0
) so that
the external source is synchronized with the system clock. If the Timer clock source is not
synchronized, a clock collision may occur and the comparison may be invalid.
See the “TMR1 - Timer1 Module with Gate Control” chapter in the device data sheet for more information on configuring Timer1.