Datasheet

 1997 Microchip Technology Inc. DS30390E-page 189
PIC16C7X
Applicable Devices 72 73 73A 74 74A 76 77
18.5 Timing Diagrams and Specifications
FIGURE 18-2: EXTERNAL CLOCK TIMING
TABLE 18-2: EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter
No.
Sym Characteristic Min Typ† Max Units Conditions
Fosc 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 — 4 MHz XT osc mode
4
5
—
—
20
200
MHz
kHz
HS osc mode
LP osc mode
1 Tosc 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 — 250 ns HS osc mode (-04)
100
50
—
—
250
250
ns
ns
HS osc mode (-10)
HS osc mode (-20)
5— —µs LP osc mode
2T
CY Instruction Cycle Time (Note 1) 200 — DC ns TCY = 4/FOSC
3 TosL,
TosH
External Clock in (OSC1) High or
Low Time
50 — — ns XT oscillator
2.5 — — µs LP oscillator
15 — — ns HS oscillator
4 TosR,
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 (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 con-
sumption. 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.
OSC1
CLKOUT
Q4 Q1 Q2 Q3 Q4 Q1
1
2
3
3
4
4