PIC16F872 Datasheet, PDF (135/160 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS FLASH Microcontroller

PIC16F872
FIGURE 14-8: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
RA4/T0CKI
40
41
42
RC0/T1OSO/T1CKI
45
46
47
48
TMR0 or
TMR1
Note: Refer to Figure 14-3 for load conditions.
TABLE 14-4: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Sym Characteristic
Min
Typ† Max Units Conditions
40*
Tt0H T0CKI High Pulse Width
No Prescaler
0.5TCY + 20
— — ns Must also meet
With Prescaler
10
— — ns ^{parameter 42}
41*
Tt0L T0CKI Low Pulse Width
No Prescaler
0.5TCY + 20
— — ns Must also meet
With Prescaler
10
— — ns parameter 42
42*
Tt0P T0CKI Period
No Prescaler
TCY + 40
— — ns
With Prescaler Greater of:
— — ns N = prescale value
20 or TCY + 40
(2, 4, ..., 256)
N
45*
Tt1H T1CKI High Time Synchronous, Prescaler = 1
0.5TCY + 20
— — ns Must also meet
Synchronous, Standard(F)
15
— — ns ^{parameter 47}
Prescaler =
2,4,8
Extended(LF)
25
— — ns
Asynchronous Standard(F)
30
— — ns
Extended(LF)
50
— — ns
46*
Tt1L T1CKI Low Time Synchronous, Prescaler = 1
0.5TCY + 20
— — ns Must also meet
Synchronous, Standard(F)
15
— — ns parameter 47
Prescaler =
2,4,8
Extended(LF)
25
— — ns
Asynchronous Standard(F)
30
— — ns
Extended(LF)
50
— — ns
47*
Tt1P T1CKI input period Synchronous Standard(F) Greater of:
— — ns N = prescale value
30 OR TCY + 40
(1, 2, 4, 8)
N
Extended(LF) Greater of:
N = prescale value
50 OR TCY + 40
(1, 2, 4, 8)
N
Asynchronous Standard(F)
60
— — ns
Extended(LF)
100
— — ns
Ft1 Timer1 oscillator input frequency range
DC
— 200 kHz
(oscillator enabled by setting bit T1OSCEN)
48 TCKEZtmr1 Delay from external clock edge to timer increment
2Tosc
— 7Tosc —
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
© 1999 Microchip Technology Inc.
Preliminary
DS30221A-page 135