PIC16C712/716
6.1 Timer2 Operation
6.2 Timer2 Interrupt
Timer2 can be used as the PWM time-base for PWM
mode of the CCP module.
The TMR2 register is readable and writable, and is
cleared on any device reset.
The input clock (FOSC/4) has a prescale option of 1:1,
1:4 or 1:16, selected by control bits
T2CKPS1:T2CKPS0 (T2CON<1:0>).
The Timer2 module has an 8-bit period register PR2.
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is ini-
tialized to FFh upon reset.
The match output of TMR2 goes through a 4-bit
postscaler (which gives a 1:1 to 1:16 scaling inclusive)
to generate a TMR2 interrupt (latched in flag bit
TMR2IF, (PIR1<1>)).
The prescaler and postscaler counters are cleared
when any of the following occurs:
• a write to the TMR2 register
• a write to the T2CON register
• any device reset (Power-on Reset, MCLR reset,
Watchdog Timer reset, or Brown-out Reset)
TMR2 is not cleared when T2CON is written.
TABLE 6-1 REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Address
0Bh,8Bh
0Ch
8Ch
11h
12h
92h
Legend:
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR,
BOR
Value on
all other
resets
INTCON GIE
PIR1
—
PIE1
—
PEIE
ADIF
ADIE
T0IE
—
—
INTE
—
—
RBIE
—
—
T0IF
CCP1IF
CCP1IE
INTF
TMR2IF
TMR2IE
RBIF
TMR1IF
TMR1IE
0000 000x 0000 000u
-00- -000 0000 -000
-0-- -000 0000 -000
TMR2
T2CON
PR2
Timer2 module’s register
0000 0000 0000 0000
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Period Register
1111 1111 1111 1111
x = unknown, u = unchanged, - = unimplemented read as '0'. Shaded cells are not used by the Timer2 module.
© 1999 Microchip Technology Inc.
Preliminary
DS41106A-page 37