PIC16C65A Microchip Technology, PIC16C65A Datasheet - Page 75

• Manufacturer Part Number: PIC16C65A
• Description: 8-Bit CMOS Microcontrollers
• Manufacturer: Microchip Technology

9.0
Timer2 is an 8-bit timer with a prescaler and a
postscaler. It is especially suitable as PWM time-base
for PWM mode of CCP module(s). TMR2 is a readable
and writable register, and is cleared on any device
reset.
The input clock (F
1:4
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 the TMR2 register 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 Timer2 module can be shut off by clearing control
bit TMR2ON (T2CON<2>) to minimize power con-
sumption.
Figure 9-2 shows the Timer2 control register. T2CON is
cleared upon reset which initializes Timer2 as shut off
with the prescaler and postscaler at a 1:1 value.
FIGURE 9-2:
Applicable Devices
61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67
1997 Microchip Technology Inc.
bit7
bit 7:
bit 6-3:
bit 2:
bit 1-0:
U-0
—
or
TIMER2 MODULE
Unimplemented: Read as '0'
TOUTPS3:TOUTPS0: Timer2 Output Postscale Select bits
0000 = 1:1 postscale
0001 = 1:2 postscale
1111 = 1:16 postscale
TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits
00 = 1:1 prescale
01 = 1:4 prescale
1x = 1:16 prescale
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0
1:16,
R/W-0
OSC
T2CON: TIMER2 CONTROL REGISTER (ADDRESS 12h)
selected
/4) has a prescale option of 1:1,
R/W-0
R/W-0
by
control
R/W-0
bits
R/W-0
9.1
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 (POR, BOR, MCLR Reset, or
TMR2 is not cleared when T2CON is written.
9.2
The output of TMR2 (before the postscaler) is fed to the
Synchronous Serial Port module which optionally uses
it to generate shift clock.
FIGURE 9-1:
Applicable Devices
61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67
Applicable Devices
61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67
R/W-0
Note 1:
WDT Reset).
Sets
TMR2
interrupt
flag bit,
TMR2IF
Postscaler
1:1 to 1:16
Timer2 Prescaler and Postscaler
Output of TMR2
TMR2 register output can be software selected by
the SSP Module as a baud clock.
R/W-0
4
TMR2
output
Reset
bit0
EQ
TIMER2 BLOCK DIAGRAM
(1)
Comparator
W = Writable bit
U = Unimplemented bit,
- n = Value at POR reset
R = Readable bit
TMR2 reg
PR2 reg
read as ‘0’
PIC16C6X
1:1, 1:4, 1:16
DS30234D-page 75
Prescaler
2
Fosc/4