PIC18F2480 MICROCHIP [Microchip Technology], PIC18F2480 Datasheet - Page 162

• Manufacturer Part Number: PIC18F2480
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2480/2580/4480/4580
14.1
Timer3 can operate in one of three modes:
• Timer
• Synchronous Counter
• Asynchronous Counter
The operating mode is determined by the clock select
bit, TMR3CS (T3CON<1>). When TMR3CS is cleared
(= 0), Timer3 increments on every internal instruction
FIGURE 14-1:
FIGURE 14-2:
DS39637A-page 160
T1OSO/T13CKI
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
T1OSO/T13CKI
Note 1: When enable bit T1OSCEN is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
Timer3 Operation
T1OSI
T1OSI
CCP1/ECCP1 Special Event Trigger
CCP1/ECCP1 Special Event Trigger
Timer1 Oscillator
T1OSCEN
T3CKPS1:T3CKPS0
T3SYNC
TMR3ON
Timer1 Oscillator
TIMER3 BLOCK DIAGRAM
TIMER3 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)
T1OSCEN
T3CKPS1:T3CKPS0
T3SYNC
TMR3ON
(1)
(1)
TCCPx
TCCPx
TMR3CS
TMR3CS
Clock
Internal
F
Clock
F
Internal
OSC
OSC
/4
/4
Preliminary
1
0
1
0
Timer1 clock input
Clear TMR3
Clear TMR3
Prescaler
1, 2, 4, 8
Prescaler
cycle (Fosc/4). When the bit is set, Timer3 increments
on every rising edge of the Timer1 external clock input
or the Timer1 oscillator if enabled.
As with Timer1, the RC1/T1OSI and RC0/T1OSO/
T13CKI pins become inputs when the Timer1 oscillator
is enabled. This means the values of TRISC<1:0> are
ignored and the pins are read as ‘0’.
1, 2, 4, 8
2
2
TMR3L
TMR3L
8
Sleep Input
Synchronize
Sleep Input
8
Synchronize
Detect
Detect
High Byte
High Byte
TMR3H
TMR3
TMR3
8
 2004 Microchip Technology Inc.
8
8
Internal Data Bus
1
0
1
0
Read TMR1L
Write TMR1L
on Overflow
on Overflow
TMR3IF
TMR3IF
Set
Set
Timer3
On/Off
Timer3
On/Off