P89LPC9401FBD NXP Semiconductors, P89LPC9401FBD Datasheet - Page 17

• Manufacturer Part Number: P89LPC9401FBD
• Description: IC, MCU 8BIT 80C51, LCD DRIVER, SMD
• Manufacturer: NXP Semiconductors

Specifications of P89LPC9401FBD

• Controller Family/series: (8051) 8052
• Core Size: 8bit
• No. Of I/o's: 23
• Program Memory Size: 8KB
• Ram Memory Size: 256Byte
• Cpu Speed: 18MHz
• Oscillator Type: External, Internal
• No. Of Timers: 4
• No.: RoHS Compliant

Philips Semiconductors
P89LPC9401_1
Preliminary data sheet
7.3.6 Clock output
7.4 On-chip RC oscillator option
7.5 Watchdog oscillator option
7.6 External clock input option
The P89LPC9401 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 RTC is not using the crystal oscillator as its clock
source. This allows external devices to synchronize to the P89LPC9401. This output is
enabled by the ENCLK bit in the TRIM register.
The frequency of this clock output is
in Idle mode, it may be turned off prior to entering idle, saving additional power.
The P89LPC9401 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 preprogrammed value
to adjust the oscillator frequency to 7.373 MHz
applications can write to the TRIM register to adjust the on-chip RC oscillator to other
frequencies.
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.
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 18 MHz. The XTAL2/P3.0 pin may be
used as a standard port pin or a clock output. When using an oscillator frequency
above 12 MHz, the reset input function of P1.5 must be enabled. An external circuit
is required to hold the device in reset at power-up until V
specified level. When system power is removed V
specified operating voltage. When using an oscillator frequency above 12 MHz, in
some applications, an external brownout detect circuit may be required to hold the
device in reset when V
8-bit two-clock 80C51 microcontroller with 32 segment
Rev. 01 — 5 September 2005
DD
falls below the minimum specified operating voltage.
1
2
that of the CCLK. If the clock output is not needed
1 % at room temperature. End-user
DD
will fall below the minimum
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
DD
P89LPC9401
has reached its
4 LCD driver
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