PIC16C745/765
FIGURE 16-8: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
41
40
42
T1OSO/T1CKI
46
45
47
48
TMR0 or
TMR1
Note: Refer to Figure 16-2 for load conditions.
TABLE 16-5: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
Sym
Characteristic
Min
Typ† Max Units Conditions
40*
TT0H
T0CKI High Pulse Width
No Prescaler
With Prescaler
No Prescaler
With Prescaler
No Prescaler
0.5 TCY + 20
—
—
—
—
—
—
—
—
—
—
—
—
ns Must also meet
parameter 42
10
0.5 TCY + 20
10
ns
41*
42*
TT0L
TT0P
T0CKI Low Pulse Width
T0CKI Period
ns Must also meet
parameter 42
ns
TCY + 40
ns
With Prescaler Greater of:
20 or TCY + 40
ns N = prescale value
(2, 4,..., 256)
N
45*
46*
47*
TT1H
TT1L
TT1P
T1CKI High Time Synchronous, Prescaler = 1
0.5 TCY + 20
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
15
ns
25
ns
Asynchronous
30
ns
50
ns
T1CKI Low Time Synchronous, Prescaler = 1
0.5 TCY + 20
ns Must also meet
parameter 47
Synchronous,
Prescaler = 2,4,8
15
25
30
50
ns
ns
ns
ns
Asynchronous
T1CKI input
period
Synchronous
Asynchronous
Greater of:
30 OR TCY + 40
ns N = prescale value
(1, 2, 4, 8)
N
Greater of:
50 OR TCY + 40
N
N = prescale value
(1, 2, 4, 8)
60
100
DC
—
—
—
—
—
ns
ns
FT1
Timer1 oscillator input frequency range
200 kHz
(oscillator enabled by setting bit T1OSCEN)
48
TCKEZTMR1 Delay from external clock edge to timer increment
2Tosc
—
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.
DS41124A-page 134
Advanced Information
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
