![](http://datasheet.mmic.net.cn/Microchip-Technology/PIC17C44-33-L_datasheet_99509/PIC17C44-33-L_155.png)
1996 Microchip Technology Inc.
DS30412C-page 155
PIC17C4X
Applicable Devices 42 R42 42A 43 R43 44
17.4
Timing Diagrams and Specications
FIGURE 17-2: EXTERNAL CLOCK TIMING
TABLE 17-2:
EXTERNAL CLOCK TIMING REQUIREMENTS
Parameter
No.
Sym
Characteristic
Min
Typ
Max
Units
Conditions
Fosc
External CLKIN Frequency
(Note 1)
DC
—
16
25
MHz
EC osc mode - PIC17C42-16
- PIC17C42-25
Oscillator Frequency
(Note 1)
DC
1
DC
—
4
16
25
2
MHz
RC osc mode
XT osc mode - PIC17C42-16
- PIC17C42-25
LF osc mode
1
Tosc
External CLKIN Period
(Note 1)
62.5
40
—
ns
EC osc mode - PIC17C42-16
- PIC17C42-25
Oscillator Period
(Note 1)
250
62.5
40
500
—
1,000
—
ns
RC osc mode
XT osc mode - PIC17C42-16
- PIC17C42-25
LF osc mode
2TCY
Instruction Cycle Time (Note 1)
160
4/Fosc
DC
ns
3
TosL,
TosH
Clock in (OSC1) High or Low Time
10
—
ns
EC oscillator
4
TosR,
TosF
Clock in (OSC1) Rise or Fall Time
—
5
ns
EC oscillator
Data in “Typ” column is at 5V, 25C unless otherwise stated. These parameters are for design guidance only and are not
tested.
These parameters are for design guidance only and are not tested, nor characterized.
Note 1:
Instruction cycle period (TCY) equals four times the input oscillator time-base period. All specied values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing code.
Exceeding these specied limits may result in unstable oscillator operation and/or higher than expected current consump-
tion. All devices are tested to operate at “min.” values with an external clock applied to the OSC1 pin.
When an external clock input is used, the “Max.” cycle time limit is “DC” (no clock) for all devices.
OSC1
OSC2
Q4
Q1
Q2
Q3
Q4
Q1
13
3
4
2
In EC and RC modes only.