|
PIC18F23K22 Datasheet, PDF (157/492 Pages) Microchip Technology – 28/40/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology | |||
|
◁ |
PIC18(L)F2X/4XK22
11.0 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 11-1) controls all
aspects of the moduleâs operation, including the
prescale selection. It is both readable and writable.
A simplified block diagram of the Timer0 module in 8-bit
mode is shown in Figure 11-1. Figure 11-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
REGISTER 11-1: 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
R/W-1
TOPS<2:0>
R/W-1
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
â1â = Bit is set
U = Unimplemented bit, read as â0â
â0â = 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 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKOUT)
T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment 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
ï£ 2010 Microchip Technology Inc.
Preliminary
DS41412B-page 157
|
▷ |