
2002 Microchip Technology Inc.
Preliminary
DS30485A-page 273
PIC18FXX39
FIGURE 23-9:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
TABLE 23-8:
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Note:
46
47
45
48
41
42
40
T0CKI
T13CKI
TMR0 or
TMR1
Param
No.
Symbol
Characteristic
Min
Max
Units
Conditions
40
Tt0H
T0CKI High Pulse Width
No Prescaler
0.5TCY + 20
—
ns
With Prescaler
10
—
ns
41
Tt0L
T0CKI Low Pulse Width
No Prescaler
0.5TCY + 20
—
ns
With Prescaler
10
—
ns
42
Tt0P
T0CKI Period
No Prescaler
TCY + 10
—
ns
With Prescaler
Greater of:
20 nS or TCY + 40
N
—
ns
N = prescale
value
(1, 2, 4,..., 256)
45
Tt1H
T13CKI High
Time
Synchronous, no prescaler
0.5TCY + 20
—
ns
Synchronous,
with prescaler
PIC18FXXXX
10
—
ns
PIC18LFXXXX
25
—
ns
Asynchronous
PIC18FXXXX
30
—
ns
PIC18LFXXXX
50
—
ns
46
Tt1L
T13CKI Low
Time
Synchronous, no prescaler
0.5TCY + 5
—
ns
Synchronous,
with prescaler
PIC18FXXXX
10
—
ns
PIC18LFXXXX
25
—
ns
Asynchronous
PIC18FXXXX
30
—
ns
PIC18LFXXXX
50
—
ns
47
Tt1P
T13CKI input
period
Synchronous
Greater of:
20 nS or TCY + 40
N
—
ns
N = prescale
value
(1, 2, 4, 8)
Asynchronous
60
—
ns
Ft1
T13CKI oscillator input frequency range
DC
50
kHz
48
Tcke2tmrI Delay from external T13CKI clock edge to timer
increment
2 TOSC
7 TOSC
—