
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
0.5TCY + 20
——
ns
Must also meet
parameter 42
With Prescaler
10
——
ns
41*
Tt0L
T0CKI Low Pulse Width
No Prescaler
0.5TCY + 20
——
ns
Must also meet
parameter 42
With Prescaler
10
——
ns
42*
Tt0P
T0CKI Period
No Prescaler
TCY + 40
——
ns
With Prescaler
Greater of:
20 or TCY + 40
N
——
ns
N = prescale value
(2, 4,..., 256)
45*
Tt1H
T1CKI High Time Synchronous, Prescaler = 1
0.5TCY + 20
——
ns
Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
Standard(F)15
——
ns
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
parameter 47
Synchronous,
Prescaler = 2,4,8
Standard(F)15
——
ns
Extended(LF)25
——
ns
Asynchronous
Standard(F)30
——
ns
Extended(LF)50
——
ns
47*
Tt1P
T1CKI input
period
Synchronous
Standard(F)
Greater of:
30 OR TCY + 40
N
——
ns
N = prescale value
(1, 2, 4, 8)
Extended(LF)
Greater of:
50 OR TCY + 40
N
N = prescale value
(1, 2, 4, 8)
Asynchronous
Standard(F)60
——
ns
Extended(LF)
100
——
ns
Ft1
Timer1 oscillator input frequency range
(oscillator enabled by setting bit T1OSCEN)
DC
—
200
kHz
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.
46
47
45
48
41
42
40
RA4/T0CKI
RC0/T1OSO/T1CKI
TMR0 or
TMR1