PIC16F872 Datasheet, PDF (132/160 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS FLASH Microcontroller

PIC16F872
FIGURE 14-4: EXTERNAL CLOCK TIMING
Q4
Q1
Q2
Q3
OSC1
CLKOUT
1
3
3
2
Q4
Q1
4
4
TABLE 14-1: EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter Sym Characteristic
No.
Min Typ† Max Units Conditions
FOSC External CLKIN Frequency
(Note 1)
DC —
DC —
4 MHz XT and RC osc mode
4 MHz HS osc mode (-04)
DC —
20 MHz HS osc mode (-20)
DC —
200 kHz LP osc mode
Oscillator Frequency
(Note 1)
DC —
0.1 —
4 MHz RC osc mode
4 MHz XT osc mode
4
—
20 MHz HS osc mode
5
—
200 kHz LP osc mode
1
TOSC External CLKIN Period
(Note 1)
250 —
250 —
—
ns XT and RC osc mode
—
ns HS osc mode (-04)
50 —
—
ns HS osc mode (-20)
5
—
—
µs LP osc mode
Oscillator Period
(Note 1)
250 —
—
ns RC osc mode
250 — 10,000 ns XT osc mode
250 —
250 ns HS osc mode (-04)
50 —
250 ns HS osc mode (-20)
5
—
—
µs LP osc mode
2
TCY Instruction Cycle Time
(Note 1)
200 TCY
DC
ns TCY = 4/FOSC
3
TosL, External Clock in (OSC1) High 100 —
—
ns XT oscillator
TosH or Low Time
2.5 —
—
µs LP oscillator
15 —
—
ns HS oscillator
4
TosR, External Clock in (OSC1) Rise — —
25
ns XT oscillator
TosF or Fall Time
——
50
ns LP oscillator
——
15
ns HS oscillator
Legend: † 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/CLKIN pin. When an external clock input is used, the "Max." cycle time limit is
"DC" (no clock) for all devices.
DS30221A-page 132
Preliminary
© 1999 Microchip Technology Inc.