PIC16LC717T-I/SO View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16LC717T-I/SO

18/20-Pin, 8-Bit CMOS Microcontrollers with 10/12-Bit A/D

Microchip Technology 

PIC16C717/770/771

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 of PR2

• SSP module optional use of TMR2 output to gen-

erate clock shift

Timer2 has a control register, shown in Register 7-1.

Timer2 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.

Additional information on timer modules is available in

the PICmicro™ Mid-Range Reference Manual,

(DS33023).

7.1 Timer2 Operation

Timer2 can be used as the PWM time-base for PWM

mode of the ECCP 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 T2CKPS<1:0>

(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: TIMER2 CONTROL REGISTER (T2CON1: 12h)

U-0

—

bit7

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0

bit0

bit 7: Unimplemented: Read as ’0’

bit 6-3:

TOUTPS<3:0>: Timer2 Output Postscale Select bits

0000 = 1:1 Postscale

0001 = 1:2 Postscale

•

•

•

1111 = 1:16 Postscale

bit 2:

TMR2ON: Timer2 On bit

1 = Timer2 is on

0 = Timer2 is off

bit 1-0:

2CKPS<1:0>: Timer2 Clock Prescale Select bits

00 = Prescaler is 1

01 = Prescaler is 4

1x = Prescaler is 16

R = Readable bit

W = Writable bit

U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

© 1999 Microchip Technology Inc.

Advanced Information

DS41120A-page 53

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