Datasheet
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 0.5T
CY + 20 ——ns Must also meet
parameter 42
With Prescaler 10 ——ns
41* Tt0L T0CKI Low Pulse Width No Prescaler 0.5T
CY + 20 ——ns Must also meet
parameter 42
With Prescaler 10 ——ns
42* Tt0P T0CKI Period No Prescaler T
CY + 40 ——ns
With Prescaler Greater of:
20 or T
CY + 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 0.5T
CY + 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 2T
OSC — 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.
Note: Refer to Figure 15-5 for load conditions.
46
47
45
48
41
42
40
RA4/T0CKI
RC0/T1OSO/T1CKI
TMR0 or
TMR1