PIC18F2331/2431/4331/4431
FIGURE 26-9:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
41
40
42
T1OSO/T1CKI
46
45
47
48
TMR0 or TMR1
TABLE 26-9: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Symbol
Characteristic
T0CKI High Pulse Width
Min
Max
Units
Conditions
VDD = 2V
40
Tt0H
No prescaler
With prescaler
No prescaler
With prescaler
No prescaler
With prescaler
0.5 TCY + 20
10
—
—
—
—
—
—
ns
ns
ns
ns
ns
41
42
Tt0L
Tt0P
T0CKI Low Pulse Width
T0CKI Period
0.5 TCY + 20
10
TCY + 10
Greater of:
20 ns or TCY + 40
N
ns N = prescale value
(1, 2, 4,..., 256)
45
46
Tt1H
Tt1L
T1CKI High Synchronous, no prescaler
Time
0.5 TCY + 20
—
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Synchronous,
with prescaler
PIC18FXX31
10
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
25
Asynchronous
30
50
T1CKI
Synchronous, no prescaler
0.5 TCY + 5
Low Time
Synchronous,
with prescaler
PIC18FXX31
10
25
30
50
PIC18LFXX31
PIC18FXX31
PIC18LFXX31
Asynchronous
47
48
Tt1P
Ft1
T1CKI Input Synchronous
Period
Greater of:
20 ns or TCY + 40
N
ns N = prescale value
(1, 2, 4, 8)
Asynchronous
60
DC
—
50
ns
kHz
—
T1CKI Oscillator Input Frequency Range
Tcke2tmrI Delay from External T1CKI Clock Edge to
Timer Increment
2 TOSC
7 TOSC
2010 Microchip Technology Inc.
DS39616D-page 351
MICROCHIP [ MICROCHIP ]
