Datasheet

PIC16C77X
DS30275B-page 42 Advance Information  1999-2013 Microchip Technology Inc.
5.1.1 TIMER1 COUNTER OPERATION
In this mode, Timer1 is being incremented via an exter-
nal source. Increments occur on a rising edge. After
Timer1 is enabled in counter mode, the module must
first have a falling edge before the counter begins to
increment.
FIGURE 5-2: TIMER1 INCREMENTING EDGE
FIGURE 5-3: TIMER1 BLOCK DIAGRAM
T1CKI
(Default high)
T1CKI
(Default low)
Note: Arrows indicate counter increments.
TMR1H
TMR1L
T1OSC
T1SYNC
TMR1CS
T1CKPS1:T1CKPS0
SLEEP input
T1OSCEN
Enable
Oscillator
(1)
FOSC/4
Internal
Clock
TMR1ON
on/off
Prescaler
1, 2, 4, 8
Synchronize
det
1
0
0
1
Synchronized
clock input
2
RC0/T1OSO/T1CKI
RC1/T1OSI
Note 1: When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
Set flag bit
TMR1IF on
Overflow
TMR1
774.book Page 42 Tuesday, January 29, 2013 12:02 PM