PIC16F818/819
FIGURE 15-4:
EXTERNAL CLOCK TIMING
Q4
Q1
Q2
Q3
Q4
4
Q1
OSC1
CLKO
1
3
3
4
2
TABLE 15-1: EXTERNAL CLOCK TIMING REQUIREMENTS
Param
Sym
Characteristic
Min Typ†
Max
Units
Conditions
No.
FOSC
External CLKI Frequency (Note 1)
DC
DC
DC
DC
0.1
4
—
—
—
—
—
—
—
—
—
—
—
—
—
—
TCY
—
—
—
—
—
—
1
20
32
4
MHz XT and RC Oscillator mode
MHz HS Oscillator mode
kHz LP Oscillator mode
MHz RC Oscillator mode
MHz XT Oscillator mode
MHz HS Oscillator mode
kHz LP Oscillator mode
ns XT and RC Oscillator mode
ns HS Oscillator mode
ms LP Oscillator mode
ns RC Oscillator mode
ns XT Oscillator mode
ns HS Oscillator mode
ms LP Oscillator mode
ns TCY = 4/FOSC
Oscillator Frequency (Note 1)
4
20
200
—
5
1
TOSC
External CLKI Period (Note 1)
Oscillator Period (Note 1)
1000
50
—
5
—
250
250
50
—
10,000
250
—
5
2
3
TCY
Instruction Cycle Time (Note 1)
200
500
2.5
15
DC
—
TOSL,
TOSH
External Clock in (OSC1) High
or Low Time
ns XT Oscillator
—
ms LP Oscillator
—
ns HS Oscillator
4
TOSR,
TOSF
External Clock in (OSC1) Rise or
Fall Time
—
25
50
15
ns XT Oscillator
—
ns LP Oscillator
—
ns HS Oscillator
†
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: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values
are based on characterization data for that particular oscillator type, under standard operating conditions,
with the device executing code. Exceeding these specified limits may result in an unstable oscillator
operation and/or higher than expected current consumption. All devices are tested to operate at “min.”
values with an external clock applied to the OSC1/CLKI pin. When an external clock input is used, the
“max.” cycle time limit is “DC” (no clock) for all devices.
2004 Microchip Technology Inc.
DS39598E-page 131
MICROCHIP [ MICROCHIP ]
