P89LPC9401FBD NXP Semiconductors, P89LPC9401FBD Datasheet - Page 24

• 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
7.15.1 Idle mode
7.15.2 Power-down mode
7.15.3 Total Power-down mode
7.16 Reset
Idle mode leaves peripherals running in order to allow them to activate the processor
when an interrupt is generated. Any enabled interrupt source or reset may terminate Idle
mode.
The Power-down mode stops the oscillator in order to minimize power consumption. The
P89LPC9401 exits Power-down mode via any reset, or certain interrupts. In Power-down
mode, the power supply voltage may be reduced to the data retention voltage V
retains the RAM contents at the point where Power-down mode was entered. SFR
contents are not guaranteed after V
recommended to wake-up the processor via reset in this case. V
within the operating range before the Power-down mode is exited.
Some chip functions continue to operate and draw power during Power-down mode,
increasing the total power used during power-down. These include: Brownout detect,
watchdog timer, Comparators (note that Comparators can be powered-down separately),
and RTC/System Timer. The internal RC oscillator is disabled unless both the RC
oscillator has been selected as the system clock and the RTC is enabled.
This is the same as Power-down mode except that the brownout detection circuitry and
the voltage comparators are also disabled to conserve additional power. The internal RC
oscillator is disabled unless both the RC oscillator has been selected as the system clock
and the RTC is enabled. If the internal RC oscillator is used to clock the RTC during
power-down, there will be high power consumption. Please use an external low frequency
clock to achieve low power with the RTC running during power-down.
The P1.5/RST pin can function as either an active-LOW reset input or as a digital input,
P1.5. The RPE (Reset Pin Enable) bit in UCFG1, when set to logic 1, enables the external
reset input function on P1.5. When cleared, P1.5 may be used as an input pin.
Remark: During a power-up sequence, The RPE selection is overridden and this pin will
always functions as a reset input. An external circuit connected to this pin should not
hold this pin LOW during a power-on sequence as this will keep the device in reset.
After power-up this input will function either as an external reset input or as a digital input
as defined by the RPE bit. Only a power-up reset will temporarily override the selection
defined by RPE bit. Other sources of reset will not override the RPE bit.
Reset can be triggered from the following sources:
•
•
•
•
•
•
External reset pin (during power-up or if user configured via UCFG1).
Power-on detect.
Brownout detect.
Watchdog timer.
Software reset.
UART break character detect reset.
8-bit two-clock 80C51 microcontroller with 32 segment
Rev. 01 — 5 September 2005
DD
has been lowered to V
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
DDR
P89LPC9401
DD
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