Datasheet

PIC18F6520/8520/6620/8620/6720/8720
DS39609C-page 320  2003-2013 Microchip Technology Inc.
26.4.3 TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 26-7: EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
TABLE 26-6: EXTERNAL CLOCK TIMING REQUIREMENTS
OSC1
CLKO
Q4 Q1 Q2 Q3 Q4 Q1
1
2
3
3
4
4
Param
No.
Symbol Characteristic Min Max Units Conditions
1A F
OSC External CLKI Frequency
(1)
DC 25 MHz EC, ECIO, PIC18FX620/X720
(-40°C to +85°C)
DC 40 MHz EC, ECIO, PIC18FX520
(-40°C to +85°C)
DC 25 MHz EC, ECIO, PIC18FX520 using external
memory interface (-40°C to +85°C)
Oscillator Frequency
(1)
DC 4 MHz RC oscillator
0.1 4 MHz XT oscillator
4 25 MHz HS oscillator
4 10 MHz HS + PLL oscillator, PIC18FX520
6 6.25 MHz HS + PLL oscillator, PIC18FX520 using
external memory interface
4 6.25 MHz HS + PLL oscillator, PIC18FX620/X720
5 200 kHz LP Oscillator mode
1T
OSC External CLKI Period
(1)
25 — ns EC, ECIO, PIC18FX620/X720
(-40°C to +85°C)
160 — ns
EC, ECIO, PIC18FX520
(-40°C to +85°C)
Oscillator Period
(1)
250 — ns RC oscillator
250 10,000 ns XT oscillator
25
100
100
250
250
160
ns
ns
ns
HS oscillator
HS + PLL oscillator, PIC18FX520
HS + PLL oscillator, PIC18FX620/X720
25 — s LP oscillator
2T
CY Instruction Cycle Time
(1)
100 — ns TCY = 4/FOSC
3T
OSL,
T
OSH
External Clock in (OSC1)
High or Low Time
30 — ns XT oscillator
2.5 — s LP oscillator
10 — ns HS oscillator
4T
OSR,
T
OSF
External Clock in (OSC1) Rise
or Fall Time
— 20 ns XT oscillator
— 50 ns LP oscillator
— 7.5 ns HS oscillator
Note 1: Instruction cycle period (T
CY) equals four times the input oscillator time base period for all configurations except PLL. 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/CLKI pin. When an external clock input is used, the “max.” cycle time limit is “DC” (no clock) for all devices.