AT89LP51 datasheet(29/113 Pages) ATMEL

Nome de Peças	AT89LP51

Descrição Electrónicos	8-bit Microcontroller with 8K Bytes In-System Programmable Flash

PDF	113 Pages

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Fabricante Electrônico	ATMEL [ATMEL Corporation]

Página de início	http://www.atmel.com

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29 / 113 page

3709B–MICRO–12/10

AT89LP51/52 - Preliminary

An optional 5 M

Ω on-chip resistor can be connected between XTAL1 and GND. This resistor can

improve the startup characteristics of the oscillator especially at higher frequencies. The resistor

can be enabled/disabled with the R1 User Fuse (See “User Configuration Fuses” on page 86.)

Figure 6-2.

Crystal Oscillator Connections

Note:

C1, C2 = 5 pF

± 5pF for Crystals

=5 pF

± 5pF for Ceramic Resonators

6.2

External Clock Source

The external clock option disables the oscillator amplifier and allows XTAL1 to be driven directly

by an external clock source as shown in Figure 6-3. XTAL2 may be left unconnected, used as

general purpose I/O P4.7, or configured to output a divided version of the system clock.

Figure 6-3.

External Clock Drive Configuration

6.3

Internal RC Oscillator

The AT89LP51/52 has an Internal Auxiliary oscillator tuned to 1.8432 MHz ±2.0%. When

enabled as the clock source, XTAL1 and XTAL2 may be used as P4.6 and P4.7 respectively.

~10 pF

~5 M

XTAL2 (P4.7)

XTAL1 (P4.6)

GND

NC GPIO

EXTERNAL

OSCILLATOR

SIGNAL

AT89LP51 Folha de dados(PDF) 29 Page - ATMEL Corporation