PIC12F609-I/PQTP MICROCHIP [Microchip Technology], PIC12F609-I/PQTP Datasheet - Page 43

• Manufacturer Part Number: PIC12F609-I/PQTP
• Description: 8-Pin Flash-Based, 8-Bit CMOS Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

5.0
The Timer0 module is an 8-bit timer/counter with the
following features:
• 8-bit timer/counter register (TMR0)
• 8-bit prescaler (shared with Watchdog Timer)
• Programmable internal or external clock source
• Programmable external clock edge selection
• Interrupt on overflow
Figure 5-1 is a block diagram of the Timer0 module.
FIGURE 5-1:
© 2006 Microchip Technology Inc.
T0CKI
WDTE
pin
Note 1: T0SE, T0CS, PSA, PS<2:0> are bits in the OPTION register.
F
OSC
T0SE
TIMER0 MODULE
2:
/4
WDTE bit is in the Configuration Word register.
Watchdog
Timer
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
T0CS
0
1
PSA
0
1
PIC12F609/615/12HV609/615
Prescaler
8-bit
Preliminary
8
PS<2:0>
5.1
When used as a timer, the Timer0 module can be used
as either an 8-bit timer or an 8-bit counter.
5.1.1
When used as a timer, the Timer0 module will
increment every instruction cycle (without prescaler).
Timer mode is selected by clearing the T0CS bit of the
OPTION register to ‘0’.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
5.1.2
When used as a counter, the Timer0 module will
increment on every rising or falling edge of the T0CKI
pin. The incrementing edge is determined by the T0SE
bit of the OPTION register. Counter mode is selected by
setting the T0CS bit of the OPTION register to ‘1’.
Note:
Timer0 Operation
8-BIT TIMER MODE
The value written to the TMR0 register can
be adjusted, in order to account for the two
instruction cycle delay when TMR0 is
written.
8-BIT COUNTER MODE
PSA
PSA
1
0
1
0
Time-out
2 T
Sync
WDT
CY
Data Bus
Set Flag bit T0IF
DS41302A-page 41
8
TMR0
on Overflow