Datasheet

 1998-2013 Microchip Technology Inc. DS30289C-page 249
PIC17C7XX
20.4 Timing Diagrams and Specifications
FIGURE 20-6: EXTERNAL CLOCK TIMING
TABLE 20-1: EXTERNAL CLOCK TIMING REQUIREMENTS
OSC1
OSC2 †
Q4
Q1 Q2
Q3 Q4 Q1
1
3
3
4
4
2
† In EC and RC modes only.
Param
No.
Sym Characteristic Min Typ† Max Units Conditions
F
OSC External CLKIN
Frequency (Note 1)
DC
DC
DC
—
—
—
8
16
33
MHz
MHz
MHz
EC osc mode - 08 devices (8 MHz devices)
- 16 devices (16 MHz devices)
- 33 devices (33 MHz devices)
Oscillator Frequency
(Note 1)
DC
2
2
2
DC
—
—
—
—
—
4
8
16
33
2
MHz
MHz
MHz
MHz
MHz
RC osc mode
XT osc mode - 08 devices (8 MHz devices)
- 16 devices (16 MHz devices)
- 33 devices (33 MHz devices)
LF osc mode
1T
OSC External CLKIN Period
(Note 1)
125
62.5
30.3
—
—
—
—
—
—
ns
ns
ns
EC osc mode - 08 devices (8 MHz devices)
- 16 devices (16 MHz devices)
- 33 devices (33 MHz devices)
Oscillator Period
(Note 1)
250
125
62.5
30.3
500
—
—
—
—
—
—
1,000
1,000
1,000
—
ns
ns
ns
ns
ns
RC osc mode
XT osc mode - 08 devices (8 MHz devices)
- 16 devices (16 MHz devices)
- 33 devices (33 MHz devices)
LF osc mode
2T
CY Instruction Cycle Time
(Note 1)
121.2 4/FOSC DC ns
3TosL,
TosH
Clock in (OSC1)
High or Low Time
10 — — ns EC oscillator
4TosR,
TosF
Clock in (OSC1)
Rise or Fall Time
— — 5 ns EC oscillator
† Data in “Typ” column is at 5V, 25°C unless otherwise stated.
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.