
2001 Microchip Technology Inc.
DS30292C-page 165
PIC16F87X
FIGURE 15-10:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
TABLE 15-4:
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Symbol
Characteristic
Min
Typ
Max Units
Conditions
40*
Tt0H
T0CKI High Pulse Width
No Prescaler
With Prescaler
No Prescaler
With Prescaler
No Prescaler
With Prescaler
0.5T
CY
+ 20
10
0.5T
CY
+ 20
10
T
CY
+ 40
Greater of:
20 or T
CY
+ 40
N
0.5T
CY
+ 20
15
25
30
50
0.5T
CY
+ 20
15
25
30
50
Greater of:
30
OR
T
CY
+ 40
N
Greater of:
50
OR
T
CY
+ 40
N
60
100
DC
—
—
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
ns
Must also meet
parameter 42
Must also meet
parameter 42
41*
Tt0L
T0CKI Low Pulse Width
42*
Tt0P
T0CKI Period
N = prescale value
(2, 4,..., 256)
45*
Tt1H
T1CKI High Time Synchronous, Prescaler = 1
Synchronous,
Prescaler = 2,4,8
Asynchronous
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Must also meet
parameter 47
Standard(
F
)
Extended(
LF
)
Standard(
F
)
Extended(
LF
)
46*
Tt1L
T1CKI Low Time
Synchronous, Prescaler = 1
Synchronous,
Prescaler = 2,4,8
Asynchronous
Must also meet
parameter 47
Standard(
F
)
Extended(
LF
)
Standard(
F
)
Extended(
LF
)
Standard(
F
)
47*
Tt1P
T1CKI input
period
Synchronous
N = prescale value
(1, 2, 4, 8)
Extended(
LF
)
N = prescale value
(1, 2, 4, 8)
Asynchronous
Standard(
F
)
Extended(
LF
)
—
—
—
—
—
200
ns
ns
kHz
Ft1
Timer1 oscillator input frequency range
(oscillator enabled by setting bit T1OSCEN)
TCKEZtmr1 Delay from external clock edge to timer increment
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.
48
2T
OSC
—
7T
OSC
—
*
Note:
Refer to Figure 15-5 for load conditions.
46
47
45
48
41
42
40
RA4/T0CKI
RC0/T1OSO/T1CKI
TMR0 or
TMR1