Datasheet

PIC16F87X
DS30292C-page 162  2001 Microchip Technology Inc.
FIGURE 15-6: EXTERNAL CLOCK TIMING
OSC1
CLKOUT
Q4 Q1 Q2 Q3 Q4 Q1
1
2
3
3
4
4
TABLE 15-1: EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter
No.
Sym Characteristic Min Typ† Max Units Conditions
F
OSC External CLKIN Frequency
(Note 1)
DC — 4 MHz XT and RC osc mode
DC — 4 MHz HS osc mode (-04)
DC — 10 MHz HS osc mode (-10)
DC — 20 MHz HS osc mode (-20)
DC — 200 kHz LP osc mode
Oscillator Frequency
(Note 1)
DC — 4 MHz RC osc mode
0.1 — 4MHzXT osc mode
4 — 10 MHz HS osc mode (-10)
4
5
—
—
20
200
MHz
kHz
HS osc mode (-20)
LP osc mode
1T
OSC External CLKIN Period
(Note 1)
250 ——ns XT and RC osc mode
250 ——ns HS osc mode (-04)
100 ——ns HS osc mode (-10)
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 ——ns HS osc mode (-04)
100 — 250 ns HS osc mode (-10)
50 — 250 ns HS osc mode (-20)
5 ——µs LP osc mode
2T
CY Instruction Cycle Time
(Note 1)
200 TCY DC ns TCY = 4/FOSC
3 TosL,
TosH
External Clock in (OSC1) High or
Low Time
100 ——ns XT oscillator
2.5 ——µs LP oscillator
15 ——ns HS oscillator
4TosR,
TosF
External Clock in (OSC1) Rise or
Fall Time
— — 25 ns XT oscillator
— — 50 ns LP oscillator
—— 15 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 (T
CY) 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.