PIC16F631_08 Datasheet, PDF (86/306 Pages) Microchip Technology – 20-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC16F631/677/685/687/689/690
6.0 TIMER1 MODULE WITH GATE
CONTROL
The Timer1 module is a 16-bit timer/counter with the
following features:
• 16-bit timer/counter register pair (TMR1H:TMR1L)
• Programmable internal or external clock source
• 3-bit prescaler
• Optional LP oscillator
• Synchronous or asynchronous operation
• Timer1 gate (count enable) via comparator or
T1G pin
• Interrupt on overflow
• Wake-up on overflow (external clock,
Asynchronous mode only)
• Time base for the Capture/Compare function
(PIC16F685/PIC16F690 only)
• Special Event Trigger (with ECCP)
(PIC16F685/PIC16F690 only)
• Comparator output synchronization to Timer1
clock
Figure 6-1 is a block diagram of the Timer1 module.
6.1 Timer1 Operation
The Timer1 module is a 16-bit incrementing counter
which is accessed through the TMR1H:TMR1L register
pair. Writes to TMR1H or TMR1L directly update the
counter.
When used with an internal clock source, the module is
a timer. When used with an external clock source, the
module can be used as either a timer or counter.
6.2 Clock Source Selection
The TMR1CS bit of the T1CON register is used to select
the clock source. When TMR1CS = 0, the clock source
is FOSC/4. When TMR1CS = 1, the clock source is
supplied externally.
Clock
Source
FOSC/4
T1CKI pin
T1LPOSC
T1OSCEN
FOSC
Mode
x
xxx
0
xxx
1
LP or
INTOSCIO
TMR1CS
0
1
1
FIGURE 6-1:
TIMER1 BLOCK DIAGRAM
TMR1GE
T1GINV
Set flag bit
TMR1IF on
Overflow
TMR1⁽²⁾
TMR1H
EN
TMR1L
TMR1ON
To C2 Comparator Module
Timer1 Clock
Synchronized
0
clock input
OSC1/T1CKI
OSC2/T1G
Oscillator
INTOSC
Without CLKOUT
T1OSCEN
1
(1)
FOSC/4
Internal
Clock
T1SYNC
1
Prescaler
1, 2, 4, 8
0
2
T1CKPS<1:0>
TMR1CS
Synchronize⁽³⁾
det
1
SYNCC2OUT^{(4) 0}
T1GSS
Note 1:
2:
3:
4:
ST Buffer is low power type when using LP oscillator, or high speed type when using T1CKI.
Timer1 register increments on rising edge.
Synchronize does not operate while in Sleep.
SYNCC2OUT is synchronized when the C2SYNC bit of the CM2CON1 register is set.
DS41262E-page 84
© 2008 Microchip Technology Inc.