PIC18F2450 Datasheet, PDF (289/320 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2450/4450
FIGURE 21-9:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
T1OSO/T1CKI
40
41
42
45
46
47
48
TMR0 or
TMR1
Note: Refer to Figure 21-4 for load conditions.
TABLE 21-11: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Symbol
Characteristic
Min
Max Units Conditions
40 Tt0H T0CKI High Pulse Width
No prescaler 0.5 TCY + 20 — ns
With prescaler
10
— ns
41 Tt0L
T0CKI Low Pulse Width
No prescaler 0.5 TCY + 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 T1CKI High Synchronous, no prescaler
0.5 TCY + 20 —
ns
Time
Synchronous, PIC18FXXXX
10
— ns
with prescaler _PIC18LFXXXX
25
—
ns VDD = 2.0V
Asynchronous PIC18FXXXX
30
— ns
PIC18LFXXXX
50
—
ns VDD = 2.0V
46 Tt1L
T1CKI Low Synchronous, no prescaler
0.5 TCY + 5 —
Time
Synchronous, PIC18FXXXX
10
—
with prescaler _PIC18LFXXXX
25
—
ns
ns
ns VDD = 2.0V
Asynchronous PIC18FXXXX
30
— ns
PIC18LFXXXX
50
—
ns VDD = 2.0V
47
Tt1P
T1CKI Input Synchronous
Period
Greater of: —
20 ns or
(TCY + 40)/N
ns N = prescale
value (1, 2, 4, 8)
Asynchronous
60
— ns
Ft1
T1CKI Oscillator Input Frequency Range
DC
50 kHz
48 Tcke2tmrI Delay from External T1CKI Clock Edge to Timer 2 TOSC 7 TOSC —
Increment
© 2006 Microchip Technology Inc.
Advance Information
DS39760A-page 287