
PIC16F627A/628A/648A
DS40044A-page 144
Preliminary
2002 Microchip Technology Inc.
TABLE 17-9:
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
0.5T
CY
+ 20*
10*
0.5T
CY
+ 20*
10*
Greater of:
T
CY
+ 40*
N
0.5T
CY
+ 20*
15*
25*
30*
50*
0.5T
CY
+ 20*
15*
25*
30*
50*
Greater of:
T
CY
+ 40*
N
Greater of:
T
CY
+ 40*
N
60*
100*
—
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
41
Tt0L
T0CKI Low Pulse Width
42
Tt0P
T0CKI Period
N = prescale
value (2, 4, ...,
256)
N = prescale
value (1, 2, 4, 8)
45
Tt1H
T1CKI High
Time
Synchronous, No Prescaler
Synchronous,
with Prescaler
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
PIC16F62X
PIC16LF62X
PIC16F62X
PIC16LF62X
Asynchronous
46
Tt1L
T1CKI Low
Time
Synchronous, No Prescaler
Synchronous,
with Prescaler
PIC16F62X
PIC16LF62X
PIC16F62X
PIC16LF62X
PIC16F62X
Asynchronous
47
Tt1P
T1CKI input
period
Synchronous
PIC16LF62X
—
—
—
Asynchronous
PIC16F62X
PIC16LF62X
—
—
—
—
—
ns
ns
kHz
Ft1
Timer1 oscillator input frequency range
(oscillator enabled by setting bit T1OSCEN)
Delay from external clock edge to timer
increment
* These parameters are characterized but not tested.
32.7
(1)
48
TCKEZt
mr1
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.
Note 1:
This oscillator is intended to work only with 32.768 kHz watch crystals and their manufactured tolerances.
Higher value crystal frequencies may not be compatible with this crystal driver.