Microchip Technology IC PIC MCU PIC18F65J15-I/PT TQFP-64 MCP PIC18F65J15-I/PT Data Sheet
Product codes
PIC18F65J15-I/PT
© 2009 Microchip Technology Inc.
DS39663F-page 163
PIC18F87J10 FAMILY
15.0 TIMER3 MODULE
The Timer3 timer/counter module incorporates these
features:
• Software selectable operation as a 16-bit timer or
features:
• Software selectable operation as a 16-bit timer or
counter
• Readable and writable 8-bit registers (TMR3H
and TMR3L)
• Selectable clock source (internal or external) with
device clock or Timer1 oscillator internal options
• Interrupt-on-overflow
• Module Reset on CCP Special Event Trigger
• Module Reset on CCP Special Event Trigger
A simplified block diagram of the Timer3 module is
shown in Figure 15-1. A block diagram of the module’s
operation in Read/Write mode is shown in Figure 15-2.
The Timer3 module is controlled through the T3CON
register (Register 15-1). It also selects the clock source
options for the CCP and ECCP modules; see
Section 17.1.1 “CCP Modules and Timer
Resources” for more information.
shown in Figure 15-1. A block diagram of the module’s
operation in Read/Write mode is shown in Figure 15-2.
The Timer3 module is controlled through the T3CON
register (Register 15-1). It also selects the clock source
options for the CCP and ECCP modules; see
Section 17.1.1 “CCP Modules and Timer
Resources” for more information.
REGISTER 15-1:
T3CON: TIMER3 CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
RD16
T3CCP2
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
bit 7
bit 0
Legend:
R = Readable bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 7
RD16: 16-Bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer3 in one 16-bit operation
0 = Enables register read/write of Timer3 in two 8-bit operations
1 = Enables register read/write of Timer3 in one 16-bit operation
0 = Enables register read/write of Timer3 in two 8-bit operations
bit 6,3
T3CCP<2:1>: Timer3 and Timer1 to CCPx Enable bits
11 = Timer3 and Timer4 are the clock sources for all CCP/ECCP modules
10 = Timer3 and Timer4 are the clock sources for ECCP3, CCP4 and CCP5;
11 = Timer3 and Timer4 are the clock sources for all CCP/ECCP modules
10 = Timer3 and Timer4 are the clock sources for ECCP3, CCP4 and CCP5;
Timer1 and Timer2 are the clock sources for ECCP1 and ECCP2
01 = Timer3 and Timer4 are the clock sources for ECCP2, ECCP3, CCP4 and CCP5;
Timer1 and Timer2 are the clock sources for ECCP1
00 = Timer1 and Timer2 are the clock sources for all CCP/ECCP modules
bit 5-4
T3CKPS<1:0>: Timer3 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 2
T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the device clock comes from Timer1/Timer3.)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
(Not usable if the device clock comes from Timer1/Timer3.)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
bit 1
TMR3CS: Timer3 Clock Source Select bit
1 = External clock input from Timer1 oscillator or T13CKI (on the rising edge after the first falling edge)
0 = Internal clock (F
1 = External clock input from Timer1 oscillator or T13CKI (on the rising edge after the first falling edge)
0 = Internal clock (F
OSC
/4)
bit 0
TMR3ON: Timer3 On bit
1 = Enables Timer3
0 = Stops Timer3
1 = Enables Timer3
0 = Stops Timer3