PIC16C7X
Applicable Devices 72 73 73A 74 74A 76 77
20.5 Timing Diagrams and Specifications
FIGURE 20-2: EXTERNAL CLOCK TIMING
Q4
Q1
Q2
Q3
OSC1
CLKOUT
1
3
3
2
Q4
Q1
4
4
TABLE 20-2: EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter Sym Characteristic
No.
Min Typ† Max Units Conditions
1
2
3
4
†
Note 1:
Fosc External CLKIN Frequency
(Note 1)
DC
—
DC
—
4
MHz XT and RC osc mode
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
—
0.1
—
4
MHz RC osc mode
4
MHz XT osc mode
4
—
5
—
20
MHz HS osc mode
200
kHz LP osc mode
Tosc External CLKIN Period
(Note 1)
250 —
250 —
—
ns XT and RC osc mode
—
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
ns HS osc mode (-10)
HS osc mode (-20)
250
ns
5
—
—
µs LP osc mode
TCY Instruction Cycle Time (Note 1)
200 TCY
DC
ns TCY = 4/FOSC
TosL, External Clock in (OSC1) High or 100 —
TosH Low Time
2.5
—
—
ns XT oscillator
—
µs LP oscillator
15
—
—
ns HS oscillator
TosR, External Clock in (OSC1) Rise or —
—
TosF 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.
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.
DS30390E-page 226
© 1997 Microchip Technology Inc.