PIC18F45K80-I Datasheet, PDF (205/622 Pages) Microchip Technology – 28/40/44/64-Pin, Enhanced Flash Microcontrollers with ECAN and nanoWatt XLP Technology

PIC18F66K80 FAMILY
13.0 TIMER0 MODULE
The Timer0 module incorporates the following features:
• Software selectable operation as a timer or
counter in both 8-bit or 16-bit modes
• Readable and writable registers
• Dedicated 8-bit, software programmable
prescaler
• Selectable clock source (internal or external)
• Edge select for external clock
• Interrupt-on-overflow
The T0CON register (Register 13-1) controls all
aspects of the module’s operation, including the
prescale selection. It is both readable and writable.
Figure 13-1 provides a simplified block diagram of the
Timer0 module in 8-bit mode. Figure 13-2 provides a
simplified block diagram of the Timer0 module in 16-bit
mode.
REGISTER 13-1: T0CON: TIMER0 CONTROL REGISTER
R/W-1
TMR0ON
bit 7
R/W-1
T08BIT
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
T0PS2
R/W-1
T0PS1
R/W-1
T0PS0
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
T08BIT: Timer0 8-Bit/16-Bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
T0CS: Timer0 Clock Source Select bit
1 = Transitions on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
T0SE: Timer0 Source Edge Select bit
1 = Increments on high-to-low transition on T0CKI pin
0 = Increments on low-to-high transition on T0CKI pin
PSA: Timer0 Prescaler Assignment bit
1 = Timer0 prescaler is not assigned; Timer0 clock input bypasses prescaler
0 = Timer0 prescaler is assigned; Timer0 clock input comes from prescaler output
T0PS<2:0>: Timer0 Prescaler Select bits
111 = 1:256 Prescale value
110 = 1:128 Prescale value
101 = 1:64 Prescale value
100 = 1:32 Prescale value
011 = 1:16 Prescale value
010 = 1:8 Prescale value
001 = 1:4 Prescale value
000 = 1:2 Prescale value
 2010-2012 Microchip Technology Inc.
DS39977F-page 205