P89LPC932BA View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

P89LPC932BA

8-bit microcontroller with accelerated two-clock 80C51 core 8 kB Flash with 512-byte data EEPROM and 768-byte RAM

Philips Electronics 

Philips Semiconductors

P89LPC932

8-bit microcontroller with accelerated two-clock 80C51 core

8.2.6 Clock output

The P89LPC932 supports a user-selectable clock output function on the

XTAL2/CLKOUT pin when crystal oscillator is not being used. This condition occurs if

another clock source has been selected (on-chip RC oscillator, watchdog oscillator,

external clock input on X1) and if the Real-Time clock is not using the crystal

oscillator as its clock source. This allows external devices to synchronize to the

P89LPC932. This output is enabled by the ENCLK bit in the TRIM register.

The frequency of this clock output is 1⁄2 that of the CCLK. If the clock output is not

needed in Idle mode, it may be turned off prior to entering Idle, saving additional

power.

8.3 On-chip RC oscillator option

The P89LPC932 has a 6-bit TRIM register that can be used to tune the frequency of

the RC oscillator. During reset, the TRIM value is initialized to a factory

pre-programmed value to adjust the oscillator frequency to 7.373 MHz, ±2.5 %.

End-user applications can write to the TRIM register to adjust the on-chip RC

oscillator to other frequencies.

8.4 Watchdog oscillator option

The watchdog has a separate oscillator which has a frequency of 400 kHz. This

oscillator can be used to save power when a high clock frequency is not needed.

8.5 External clock input option

In this configuration, the processor clock is derived from an external source driving

the XTAL1/P3.1 pin. The rate may be from 0 Hz up to 12 MHz. The XTAL2/P3.0 pin

may be used as a standard port pin or a clock output.

XTAL1

XTAL2

High freq.

Med. freq.

Low freq.

RC

RCCLK

OSCILLATOR

(7.3728 MHz ±2.5%)

WATCHDOG

OSCILLATOR

(400 kHz +20% -30%)

OSCCLK

DIVM CCLK

÷2

PCLK

PCLK

TIMER 0 and

TIMER 1

I2C

SPI

UART

Fig 6. Block diagram of oscillator control.

RTC

CPU

WDT

32× PLL

CCU

002aaa515

9397 750 12379

Product data

Rev. 04 — 06 January 2004

© Koninklijke Philips Electronics N.V. 2004. All rights reserved.

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