PIC16F87XA
FIGURE 17-8:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
RA4/T0CKI
41
40
42
RC0/T1OSO/T1CKI
46
45
47
48
TMR0 or
TMR1
Note: Refer to Figure 17-3 for load conditions.
TABLE 17-6: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Symbol
Characteristic
T0CKI High Pulse Width
Min
Typ† Max Units
Conditions
40* Tt0H
41* Tt0L
42* Tt0P
No Prescaler
With Prescaler
No Prescaler
With Prescaler
No Prescaler
With Prescaler
0.5TCY + 20
10
—
—
—
—
—
—
—
—
—
—
—
—
ns Must also meet
parameter 42
ns
ns Must also meet
T0CKI Low Pulse Width
T0CKI Period
0.5TCY + 20
10
parameter 42
ns
ns
TCY + 40
Greater of:
20 or TCY + 40
N
ns N = prescale value
(2, 4,..., 256)
45* Tt1H
46* Tt1L
47* Tt1P
T1CKI High Time Synchronous, Prescaler = 1
0.5TCY + 20
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
Standard(F)
Extended(LF)
Standard(F)
Extended(LF)
15
ns
ns
ns
ns
25
Asynchronous
30
50
T1CKI Low Time Synchronous, Prescaler = 1
0.5TCY + 20
ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
Standard(F)
Extended(LF)
Standard(F)
Extended(LF)
Standard(F)
15
25
30
50
ns
ns
ns
ns
Asynchronous
T1CKI input
period
Synchronous
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
100
DC
—
—
—
—
—
ns
ns
Extended(LF)
Ft1
Timer1 Oscillator Input Frequency Range
(oscillator enabled by setting bit T1OSCEN)
200 kHz
48
TCKEZtmr1 Delay from external clock edge to timer increment
These parameters are characterized but not tested.
2TOSC
—
7TOSC
—
*
†
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
2001 Microchip Technology Inc.
Advance Information
DS39582A-page 183
MICROCHIP [ MICROCHIP ]
