
PIC18F/LF1XK50
DS41350E-page 112
Preliminary
2010 Microchip Technology Inc.
12.2
Timer2 Interrupt
Timer2 can also generate an optional device interrupt.
The Timer2 output signal (TMR2-to-PR2 match) pro-
vides the input for the 4-bit output counter/postscaler.
This counter generates the TMR2 match interrupt flag
which is latched in TMR2IF of the PIR1 register. The
interrupt is enabled by setting the TMR2 Match Inter-
rupt Enable bit, TMR2IE of the PIE1 register.
A range of 16 postscale options (from 1:1 through 1:16
inclusive) can be selected with the postscaler control
bits, T2OUTPS<3:0> of the T2CON register.
12.3
Timer2 Output
The unscaled output of TMR2 is available primarily to
the CCP modules, where it is used as a time base for
operations in PWM mode.
Timer2 can be optionally used as the shift clock source
for the MSSP module operating in SPI mode. Addi-
FIGURE 12-1:
TIMER2 BLOCK DIAGRAM
TABLE 12-1:
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
INTCON GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RABIE
TMR0IF
INT0IF
RABIF
PIR1
—
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
PIE1
—
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
IPR1
—
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
TMR2
Timer2 Register
T2CON
—
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON
T2CKPS1
T2CKPS0
PR2
Timer2 Period Register
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.
Comparator
TMR2 Output
TMR2
Postscaler
Prescaler
PR2
2
FOSC/4
1:1 to 1:16
1:1, 1:4, 1:16
4
T2OUTPS<3:0>
T2CKPS<1:0>
Set TMR2IF
Internal Data Bus
8
Reset
TMR2/PR2
8
(to PWM or MSSP)
Match