PIC18C658 MICROCHIP [Microchip Technology], PIC18C658 Datasheet - Page 118

• Manufacturer Part Number: PIC18C658
• Description: High-Performance Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18CXX8
11.1
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
The operating mode is determined by the clock select
bit, TMR1CS (T1CON register).
FIGURE 11-1: TIMER1 BLOCK DIAGRAM
FIGURE 11-2: TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
DS30475A-page 118
T13CKI/T1OSO
Note 1:
Note 1:
T13CKI/T1OSO
T1OSI
TMR1IF
Overflow
Interrupt
Flag bit
Data Bus<7:0>
Timer1 Operation
Write TMR1L
Read TMR1L
TMR1IF
Overflow
Interrupt
Flag Bit
When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This reduces power drain.
T1OSI
When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off. This reduces power drain.
8
T1OSC
high byte
TMR1H
Timer 1
8
TMR1H
T1OSC
8
TMR1
TMR1
Oscillator
Enable
T1OSCEN
T1OSCEN
Enable
Oscillator
TMR1L
TMR1L
Advanced Information
8
(1)
CLR
(1)
Clock
Internal
F
OSC
Clock
Internal
Fosc/4
TMR1ON
/4
CCP Special Event Trigger
On/Off
TMR1ON
TMR1CS
Special Event Trigger
On/Off
1
0
When TMR1CS is clear, Timer1 increments every
instruction cycle. When TMR1CS is set, Timer1 incre-
ments on every rising edge of the external clock input
or the Timer1 oscillator, if enabled.
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RC1/T1OSI and RC0/T1OSO/T1CKI pins
become inputs. That is, the TRISC<1:0> value is
ignored.
Timer1 also has an internal “RESET input”. This
RESET can be generated by the CCP module
(Section 14.0).
TMR1CS
1
0
T1CKPS1:T1CKPS0
T1SYNC
Prescaler
1, 2, 4, 8
T1CKPS1:T1CKPS0
T1SYNC
Prescaler
1, 2, 4, 8
0
1
2
0
1
2
 2000 Microchip Technology Inc.
Synchronized
Clock Input
Synchronize
SLEEP Input
Synchronized
Clock Input
Synchronize
SLEEP Input
det
det