P89LPC9381 NXP Semiconductors, P89LPC9381 Datasheet - Page 24

• Manufacturer Part Number: P89LPC9381
• Description: The P89LPC9381 is a single-chip microcontroller, available in low-cost packages, basedon a high performance processor architecture that executes instructions in two to fourclocks, six times the rate of standard 80C51 devices
• Manufacturer: NXP Semiconductors

Philips Semiconductors
P89LPC9381_1
Product data sheet
7.14.2 Power-on detection
7.15.1 Idle mode
7.15.2 Power-down mode
7.15.3 Total Power-down mode
7.15 Power reduction modes
Brownout detection may be enabled or disabled in software.
If brownout detection is enabled, the brownout condition occurs when V
brownout trip voltage, V
rises above V
below 2.7 V, BOE should be left in the unprogrammed state so that the device can operate
at 2.4 V, otherwise continuous brownout reset may prevent the device from operating.
For correct activation of brownout detect, the V
Please see
The Power-on detect has a function similar to the brownout detect, but is designed to work
as power comes up initially, before the power supply voltage reaches a level where
brownout detect can work. The POF flag in the RSTSRC register is set to indicate an
initial power-up condition. The POF flag will remain set until cleared by software.
The P89LPC9381 supports three different power reduction modes. These modes are Idle
mode, Power-down mode, and Total Power-down mode.
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
P89LPC9381 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.
Table 10 “Static characteristics”
bo
. If the P89LPC9381 device is to operate with a power supply that can be
Rev. 01 — 8 September 2006
bo
(see
Table 10 “Static
DD
has been lowered to V
for specifications.
characteristics”), and is negated when V
DD
rise and fall times must be observed.
8-bit microcontroller with 10-bit ADC
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
DDR
P89LPC9381
DD
, therefore it is highly
must be raised to
DD
falls below the
DDR
). This
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DD