Microchip Technology MCP1630DM-DDBS1 Data Sheet
PIC12F683
DS41211D-page 44
©
2007 Microchip Technology Inc.
6.0
TIMER1 MODULE WITH GATE
CONTROL
CONTROL
The Timer1 module is a 16-bit timer/counter with the
following features:
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)
• Special Event Trigger (with CCP)
• 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.
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.
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 =
the clock source. When TMR1CS =
0
, the clock source
is F
OSC
/4. When TMR1CS =
1
, the clock source is
supplied externally.
FIGURE 6-1:
TIMER1 BLOCK DIAGRAM
Clock Source
TMR1CS
F
OSC
/4
0
T1CKI pin
1
TMR1H
TMR1L
Oscillator
T1SYNC
T1CKPS<1:0>
Prescaler
1, 2, 4, 8
Synchronize
(3)
det
1
0
0
1
Synchronized
clock input
2
Set flag bit
TMR1IF on
Overflow
TMR1IF on
Overflow
TMR1
(2)
TMR1GE
TMR1ON
T1OSCEN
1
0
COUT
T1GSS
T1GINV
To Comparator Module
Timer1 Clock
Timer1 Clock
TMR1CS
OSC2/T1G
OSC1/T1CKI
Note
1:
ST Buffer is low power type when using LP oscillator, or high speed type when using T1CKI.
2:
Timer1 register increments on rising edge.
3:
Synchronize does not operate while in Sleep.
(1)
EN
INTOSC
Without CLKOUT
F
OSC
/4
Internal
Clock