Datasheet

PIC16F818/819
DS39598F-page 132  2001-2013 Microchip Technology Inc.
FIGURE 15-8: 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* T
T0H T0CKI High Pulse Width No Prescaler 0.5 TCY + 20 — — ns Must also meet
parameter 42
With Prescaler 10 — — ns
41* T
T0L T0CKI Low Pulse Width No Prescaler 0.5 TCY + 20 — — ns Must also meet
parameter 42
With Prescaler 10 — — ns
42* T
T0P T0CKI Period No Prescaler TCY + 40 ——ns
With Prescaler Greater of:
20 or T
CY + 40
N
— — ns N = prescale value
(2, 4, ..., 256)
45* T
T1H T1CKI High
Time
Synchronous, Prescaler = 1 0.5 TCY + 20 — — ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
PIC16F818/819 15 — — ns
PIC16LF818/819 25 — — ns
Asynchronous PIC16F818/819 30 — — ns
PIC16LF818/819 50 — — ns
46* T
T1L T1CKI Low Time Synchronous, Prescaler = 1 0.5 TCY + 20 — — ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
PIC16F818/819 15 — — ns
PIC16LF818/819 25 — — ns
Asynchronous PIC16F818/819 30 — — ns
PIC16LF818/819 50 — — ns
47* T
T1P T1CKI Input
Period
Synchronous PIC16F818/819 Greater of:
30 or T
CY + 40
N
— — ns N = prescale
value (1, 2, 4, 8)
PIC16LF818/819 Greater of:
50 or T
CY + 40
N
N = prescale
value (1, 2, 4, 8)
Asynchronous PIC16F818/819 60 — — ns
PIC16LF818/819 100 — — ns
F
T1 Timer1 Oscillator Input Frequency Range
(Oscillator enabled by setting bit T1OSCEN)
DC — 32.768 kHz
48 TCKEZ
TMR1 Delay from External Clock Edge to Timer Increment 2 TOSC —7 TOSC —
* 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.
Note: Refer to Figure 15-3 for load conditions.
46
47
45
48
41
42
40
RA4/T0CKI
RB6/T1OSO/T1CKI
TMR0 or TMR1