
PIC16F62X
DS40300C-page 44
Preliminary
2003 Microchip Technology Inc.
6.3
Timer0 Prescaler
An 8-bit counter is available as a prescaler for the
Timer0 module, or as a postscaler for the Watchdog
Timer. A prescaler assignment for the Timer0 module
means that there is no postscaler for the Watchdog
Timer, and vice-versa.
The PSA and PS2:PS0 bits (OPTION<3:0>) determine
the prescaler assignment and prescale ratio.
When assigned to the Timer0 module, all instructions
writing
to
the
TMR0
register
(e.g.,
CLRF 1,
MOVWF 1, BSF 1, x....etc.
) will clear the pres-
caler. When assigned to WDT, a CLRWDT instruction
will clear the prescaler along with the Watchdog Timer.
The prescaler is not readable or writable.
FIGURE 6-1:
BLOCK DIAGRAM OF THE TIMER0/WDT
T0CKI
T0SE
Pin
F
OSC/4
SYNC
2
Cycles
TMR0 reg
8-to-1MUX
Watchdog
Timer
PSA
01
0
1
WDT
Timeout
PS0 - PS2
8
.
PSA
WDT Enable bit
0
1
0
1
Data Bus
Set Flag Bit T0IF
on Overflow
8
PSA
Note
1: T0SE, T0CS, PSA, PS0-PS2 are bits in the Option Register.
T0CS
WDT Postscaler/
TMR0 Prescaler