16F84 MICROCHIP [Microchip Technology], 16F84 Datasheet - Page 30

• Manufacturer Part Number: 16F84
• Description: 18-pin Flash/EEPROM 8-Bit Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

PIC16F8X
FIGURE 6-5:
FIGURE 6-6:
DS30430C-page 30
RA4/T0CKI
CLKOUT (= Fosc/4)
WDT Enable bit
Note: T0CS, T0SE, PSA, PS2:PS0 are bits in the OPTION_REG register.
Note 1:
pin
Watchdog
Timer
2:
3:
Delay from clock input change to TMR0 increment is 3Tosc to 7Tosc. (Duration of Q = Tosc).
Therefore, the error in measuring the interval between two edges on TMR0 input =
External clock if no prescaler selected, Prescaler output otherwise.
The arrows
Prescaler Out (Note 2)
Output After Sampling
Increment TMR0 (Q4)
Ext. Clock/Prescaler
TIMER0 TIMING WITH EXTERNAL CLOCK
BLOCK DIAGRAM OF THE TMR0/WDT PRESCALER
Ext. Clock Input or
T0SE
indicate where sampling occurs. A small clock pulse may be missed by sampling.
0
1
PSA
TMR0
M
U
X
0
1
T0CS
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
M
U
X
0
8-bit Prescaler
8 - to - 1MUX
time-out
8
M U X
WDT
1
0
T0
1
PSA
M
U
X
PSA
PS2:PS0
Cycles
SYNC
2
T0 + 1
TMR0 register
4Tosc max.
1998 Microchip Technology Inc.
Data Bus
(Note 3)
8
T0 + 2
Set bit T0IF
on overflow