PIC16C774T-I/SO View Datasheet(PDF) - Microchip Technology
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PIC16C774T-I/SO Datasheet PDF : 202 Pages
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PIC16C77X
6.0 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 Figure 6-1.
Timer2 can be shut off by clearing control bit TMR2ON
(T2CON<2>) to minimize power consumption.
Figure 6-2 is a simplified block diagram of the Timer2
module.
Additional information on timer modules is available in
the PICmicro™ Mid-Range Reference Manual,
(DS33023).
6.1 Timer2 Operation
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 match output of TMR2 goes through a 4-bit post-
scaler (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.
FIGURE 6-1: T2CON: TIMER2 CONTROL REGISTER (ADDRESS 12h)
U-0
—
bit7
bit 7:
bit 6-3:
bit 2:
bit 1-0:
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
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 = 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
1999-2013 Microchip Technology Inc.
Advance Information
DS30275B-page 45
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