PIC16CR58A Microchip Technology, PIC16CR58A Datasheet - Page 68

• Manufacturer Part Number: PIC16CR58A
• Description: ROM-Based 8-Bit CMOS Microcontroller Series
• Manufacturer: Microchip Technology

PIC16C6X
7.3
An 8-bit counter is available as a prescaler for the
Timer0 module or as a postscaler for the Watchdog
Timer (WDT), respectively (Figure 7-6). For simplicity,
this counter is being referred to as “prescaler” through-
out this data sheet. Note that the prescaler may be
used by either the Timer0 module or the Watchdog
Timer, but not both. Thus, a prescaler assignment for
the Timer0 module means that there is no prescaler for
the Watchdog Timer, and vice-versa.
FIGURE 7-6:
DS30234D-page 68
Applicable Devices
61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67
RA4/T0CKI
CLKOUT (=Fosc/4)
WDT Enable bit
pin
Watchdog
Timer
Prescaler
Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION<5:0>).
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
T0SE
0
1
PSA
M
U
X
0
1
T0CS
M
U
X
0
8-bit Prescaler
8 - to - 1MUX
Time-out
8
M U X
WDT
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
MOVWF TMR0, BSF TMR0,bitx) will clear the pres-
caler count. When assigned to the Watchdog Timer, a
CLRWDT instruction will clear the Watchdog Timer and
the prescaler count. 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
1997 Microchip Technology Inc.
TMR0 reg
Data Bus
8
Set flag bit T0IF
on Overflow
TMR0,