P89LPC934 PHILIPS [NXP Semiconductors], P89LPC934 Datasheet - Page 24

• Manufacturer Part Number: P89LPC934
• Description: 8-bit microcontroller with accelerated two-clock 80C51 core 4 kB/8 kB 3 V byte-erasable Flash with 8-bit A/D converters
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
9397 750 15113
Product data sheet
8.3.1 Clock definitions
8.3.2 CPU clock (OSCCLK)
8.3.3 Low speed oscillator option
8.3.4 Medium speed oscillator option
8.3.5 High speed oscillator option
8.3.6 Clock output
8.2 Enhanced CPU
8.3 Clocks
The P89LPC933/934/935/936 uses an enhanced 80C51 CPU which runs at six times the
speed of standard 80C51 devices. A machine cycle consists of two CPU clock cycles, and
most instructions execute in one or two machine cycles.
The P89LPC933/934/935/936 device has several internal clocks as defined below:
OSCCLK — Input to the DIVM clock divider. OSCCLK is selected from one of four clock
sources (see
Section 8.8 “CCLK modification: DIVM
Remark: f
CCLK — CPU clock; output of the clock divider. There are two CCLK cycles per machine
cycle, and most instructions are executed in one to two machine cycles (two or four CCLK
cycles).
RCCLK — The internal 7.373 MHz RC oscillator output.
PCLK — Clock for the various peripheral devices and is
The P89LPC933/934/935/936 provides several user-selectable oscillator options in
generating the CPU clock. This allows optimization for a range of needs from high
precision to lowest possible cost. These options are configured when the flash is
programmed and include an on-chip watchdog oscillator, an on-chip RC oscillator, an
oscillator using an external crystal, or an external clock source. The crystal oscillator can
be optimized for low, medium, or high frequency crystals covering a range from 20 kHz to
18 MHz.
This option supports an external crystal in the range of 20 kHz to 100 kHz. Ceramic
resonators are also supported in this configuration.
This option supports an external crystal in the range of 100 kHz to 4 MHz. Ceramic
resonators are also supported in this configuration.
This option supports an external crystal in the range of 4 MHz to 18 MHz. Ceramic
resonators are also supported in this configuration.
The P89LPC933/934/935/936 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,
osc
Figure
is defined as the OSCCLK frequency.
8) and can also be optionally divided to a slower frequency (see
Rev. 06 — 20 June 2005
8-bit microcontroller with accelerated two-clock 80C51 core
P89LPC933/934/935/936
register”).
CCLK
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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