at89s51-33sc ATMEL Corporation, at89s51-33sc Datasheet - Page 12

• Manufacturer Part Number: at89s51-33sc
• Description: At89s51, 8-bit Microcontroller With 4k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

11. Oscillator Characteristics
12
AT89S51
Figure 10-1. Interrupt Sources
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be
configured for use as an on-chip oscillator, as shown in
ceramic resonator may be used. To drive the device from an external clock source, XTAL2
should be left unconnected while XTAL1 is driven, as shown in
requirements on the duty cycle of the external clock signal, since the input to the internal clock-
ing circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low
time specifications must be observed.
Figure 11-1. Oscillator Connections
Note:
C1, C2
= 30 pF ± 10 pF for Crystals
= 40 pF ± 10 pF for Ceramic Resonators
INT0
INT1
TF0
TF1
RI
TI
0
1
0
1
C2
C1
XTAL2
XTAL1
GND
Figure
IE0
IE1
11-1. Either a quartz crystal or
Figure
11-2. There are no
2487C–MICRO–03/05