PIC16C926 Microchip Technology Inc., PIC16C926 Datasheet - Page 46

• Manufacturer Part Number: PIC16C926
• Description: 64/68-pin Cmos Microcontrollers With Lcd Driver
• Manufacturer: Microchip Technology Inc.

PIC16C925/926
5.3
An 8-bit counter is available as a prescaler for the
Timer0 module, or as a postscaler for the Watchdog
Timer (Figure 5-6). For simplicity, this counter is being
referred to as “prescaler” throughout this data sheet.
Note that the prescaler may be used by either the
Timer0 module or the WDT, but not both. Thus, a pres-
caler assignment for the Timer0 module means that
there is no prescaler for the Watchdog Timer, and vice-
versa.
FIGURE 5-6:
DS39544A-page 44
CLKOUT (= F
RA4/T0CKI
WDT Enable bit
Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION<5:0>).
pin
Watchdog
Prescaler
Timer
OSC
/4)
T0SE
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
0
1
PSA
M
U
X
0
1
T0CS
M
U
X
0
8-bit Prescaler
8 - to - 1 MUX
Time-out
8
M U X
WDT
Preliminary
1
0
1
PSA
M
U
X
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 prescaler count. When
assigned to WDT, a CLRWDT instruction will clear the
prescaler count along with the Watchdog Timer. The
prescaler is not readable or writable.
Note:
PSA
PS2:PS0
Cycles
SYNC
Writing to TMR0 when the prescaler is
assigned to Timer0, will clear the prescaler
count, but will not change the prescaler
assignment.
2
TMR0 reg
Data Bus
2001 Microchip Technology Inc.
8
Set Flag bit TMR0IF
on Overflow