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