Microchip Technology MCU PIC PIC18F87K22-I/PTRSL TQFP-80 MCP PIC18F87K22-I/PTRSL Data Sheet
Product codes
PIC18F87K22-I/PTRSL
2009-2011 Microchip Technology Inc.
DS39960D-page 197
PIC18F87K22 FAMILY
14.0
TIMER1 MODULE
The Timer1 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 (TMR1H
and TMR1L)
• Selectable clock source (internal or external) with
device clock or SOSC oscillator internal options
• Interrupt-on-overflow
• Reset on ECCP Special Event Trigger
• Timer with gated control
• Reset on ECCP Special Event Trigger
• Timer with gated control
displays a simplified block diagram of the
Timer1 module.
The Timer1 oscillator can also be used as a low-power
clock source for the microcontroller in power-managed
operation. The Timer1 can also work on the SOSC
oscillator.
Timer1 is controlled through the T1CON Control
register (
The Timer1 oscillator can also be used as a low-power
clock source for the microcontroller in power-managed
operation. The Timer1 can also work on the SOSC
oscillator.
Timer1 is controlled through the T1CON Control
register (
). It also contains the Secondary
Oscillator Enable bit (SOSCEN). Timer1 can be
enabled or disabled by setting or clearing control bit,
TMR1ON (T1CON<0>).
The F
enabled or disabled by setting or clearing control bit,
TMR1ON (T1CON<0>).
The F
OSC
clock source should not be used with the
ECCP capture/compare features. If the timer will be
used with the capture or compare features, always
select one of the other timer clocking options.
used with the capture or compare features, always
select one of the other timer clocking options.
REGISTER 14-1:
T1CON: TIMER1 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
TMR1CS1
TMR1CS0
T1CKPS1
T1CKPS0
SOSCEN
T1SYNC
RD16
TMR1ON
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 7-6
TMR1CS<1:0>:
Timer1 Clock Source Select bits
10
= Timer1 clock source is either from a pin or oscillator, depending on the SOSCEN bit:
SOSCEN = 0:
External clock from the T1CKI pin (on the rising edge).
SOSCEN = 1:
SOSCEN = 1:
Depending on the SOSCSEL Configuration bit, the clock source is either a crystal oscillator on the
SOSCI/SOSCO pins or an internal clock from the SCLKI pin.
01
SOSCI/SOSCO pins or an internal clock from the SCLKI pin.
01
= Timer1 clock source is the system clock (F
OSC
)
(
)
00
= Timer1 clock source is the instruction clock (F
OSC
/4)
bit 5-4
T1CKPS<1:0>:
Timer1 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
bit 3
SOSCEN:
SOSC Oscillator Enable bit
1
= SOSC is enabled and available for Timer1
0
= SOSC is disabled for Timer1
The oscillator inverter and feedback resistor are turned off to eliminate power drain.
bit 2
T1SYNC:
Timer1 External Clock Input Synchronization Select bit
TMR1CS<1:0> = 10:
1
1
= Do not synchronize external clock input
0
= Synchronize external clock input
TMR1CS<1:0> = 0x:
This bit is ignored. Timer1 uses the internal clock when TMR1CS<1:0> = 1x.
bit 1
RD16:
16-Bit Read/Write Mode Enable bit
1
= Enables register read/write of Timer1 in one 16-bit operation
0
= Enables register read/write of Timer1 in two 8-bit operations
bit 0
TMR1ON:
Timer1 On bit
1
= Enables Timer1
0
= Stops Timer1
Note 1:
The F
OSC
clock source should not be selected if the timer will be used with the ECCP capture/compare features.