PIC16F946 Datasheet, PDF (95/274 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt Technology

PIC16F946
7.0 TIMER2 MODULE
The Timer2 module timer has the following features:
• 8-bit timer (TMR2 register)
• 8-bit period register (PR2)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4, 1:16)
• Software programmable postscaler (1:1 to 1:16)
• Interrupt on TMR2 match with PR2
Timer2 has a control register shown in Register 7-1.
TMR2 can be shut-off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption.
Figure 7-1 is a simplified block diagram of the Timer2
module. The prescaler and postscaler selection of
Timer2 are controlled by this register.
7.1 Timer2 Operation
Timer2 can be used as the PWM time base for the
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 T2CKPSx
(T2CON<1:0>). 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.
REGISTER 7-1:
T2CON – TIMER2 CONTROL REGISTER (ADDRESS: 12h)
U-0
R/W-0
R/W-0
R/W-0
R/W-0 R/W-0
— TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON
bit 7
R/W-0
T2CKPS1
R/W-0
T2CKPS0
bit 0
bit 7
bit 6-3
bit 2
bit 1-0
Unimplemented: Read as ‘0’
TOUTPS<3:0>: 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
T2CKPS<1:0>: Timer2 Clock Prescale Select bits
00 =Prescaler is 1
01 =Prescaler is 4
1x =Prescaler is 16
Legend:
R = Readable bit
- n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
© 2005 Microchip Technology Inc.
Preliminary
DS41265A-page 93