p89lpc904 NXP Semiconductors, p89lpc904 Datasheet - Page 14

• Manufacturer Part Number: p89lpc904
• Description: 8-bit Microcontrollers With Two-clock Accelerated 80c51 Core 1 Kb 3 V Byte-erasable Flash With 8-bit A/d Converter
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 13521
Preliminary data
8.5 External clock input option
In this configuration, the processor clock is derived from an external source driving
the P0.5/CMPREF/CLKIN pin. The rate may be from 0 Hz up to 12 MHz. The
P0.5/CMPREF/CLKIN pin may also be used as a standard port pin.
Fig 4. Block diagram of oscillator control.
OSCILLATOR
(7.3728 MHz)
OSCILLATOR
WATCHDOG
(400 kHz)
clkin
RC
Rev. 02 — 25 June 2004
8-bit microcontrollers with two-clock accelerated 80C51 core
OSCCLK
GENERATOR
BAUD RATE
DIVM
CCLK
UART
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
2
PCLK
P89LPC904
TIMERS 0 & 1
002aaa782
ADC1/
DAC1
WDT
RTC
CPU
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