P89LPC932 Philips Semiconductors, P89LPC932 Datasheet - Page 24

• Manufacturer Part Number: P89LPC932
• Description: 80C51 8-bit microcontroller with two-clock core 8 KB 3 V low-power Flash with 512-byte data EEPROM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 12379
Product data
8.13.2 Power-on detection
8.14.1 Idle mode
8.14.2 Power-down mode
8.14.3 Total Power-down mode
8.14 Power reduction modes
If Brownout detection is enabled, the operating voltage range for V
and the brownout condition occurs when V
V
above V
2.4 V to 3.6 V. If the P89LPC932 device is to operate with a power supply that can be
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
observed. 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 P89LPC932 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 P89LPC932 exits Power-down mode via any reset, or certain interrupts. In
Power-down mode, the power supply voltage may be reduced to the RAM keep-alive
voltage V
was entered. SFR contents are not guaranteed after V
therefore it is highly recommended to wake up the processor via reset in this case.
V
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 Real-Time Clock (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
BO
DD
(see
must be raised to within the operating range before the Power-down mode is
BO
RAM
Table 8 “DC electrical
. If brownout detection is disabled, the operating voltage range for V
. This retains the RAM contents at the point where Power-down mode
Rev. 04 — 06 January 2004
8-bit microcontroller with accelerated two-clock 80C51 core
Table 8 “DC electrical characteristics”
characteristics”), and is negated when V
DD
falls below the brownout trip voltage,
DD
rise and fall times must be
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
DD
has been lowered to V
P89LPC932
for specifications.
DD
is 2.7 V to 3.6 V,
DD
rises
24 of 60
DD
RAM
is
,