AT89 datasheet(21/41 Pages) ATMEL

Part #	AT89

Description	8-Bit Microcontroller with 8K Bytes Flash

PDF	41 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

Logo

21 / 41 page

AT89S8252

0401F–MICRO–11/03

Oscillator

Characteristics

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 Figure 11. Either a

quartz crystal or 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

Figure 12. There are no requirements on the duty cycle of the external clock signal,

since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but

minimum and maximum voltage high and low time specifications must be observed.

Figure 11. Oscillator Connections

Note:

C1, C2 =

30 pF ± 10 pF for Crystals

40 pF ± 10 pF for Ceramic Resonators

Figure 12. External Clock Drive Configuration

AT89 Datasheet(PDF) 21 Page - ATMEL Corporation