P89LPC915 PHILIPS [NXP Semiconductors], P89LPC915 Datasheet - Page 40

• Manufacturer Part Number: P89LPC915
• Description: 8-bit microcontrollers with accelerated two-clock 80C51 core 2 kB 3 V Flash with 8-bit A/D converter
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
9397 750 14397
Product data
9.12.7 Additional port features
9.13.1 Brownout detection
9.13.2 Power-on detection
9.13 Power monitoring functions
9.14 Power reduction modes
After power-up, all pins are in Input-Only mode. After power-up all I/O pins except
P1.5, may be configured by software.
Every output on the P89LPC915/916/917 has been designed to sink typical LED
drive current. However, there is a maximum total output current for all ports which
must not be exceeded. Please refer to
detailed specifications.
All port pins that can function as an output have slew rate controlled outputs to limit
noise generated by quickly switching output signals. The slew rate is factory-set to
approximately 10 ns rise and fall times.
The P89LPC915/916/917 incorporates power monitoring functions designed to
prevent incorrect operation during initial power-up and power loss or reduction during
operation. This is accomplished with two hardware functions: Power-on detect and
Brownout detect.
The Brownout detect function determines if the power supply voltage drops below a
certain level. The default operation is for a Brownout detection to cause a processor
reset, however, it may alternatively be configured to generate an interrupt.
Brownout detection may be enabled or disabled in software.
If Brownout detection is enabled, the brownout condition occurs when V
the brownout trip voltage, V
negated when V
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 P89LPC915/916/917 supports three different power reduction modes. These
modes are Idle mode, Power-down mode, and total Power-down mode.
•
•
Pin P1.5 is input only.
SCL/T0/P1.2 and SDA/INTO/P1.3 may only be configured to be either input-only or
open drain.
DD
Rev. 04 — 17 December 2004
rises above V
8-bit microcontrollers with accelerated two-clock 80C51 core
Table 13 “DC electrical characteristics”
BO
(see
BO
Table 13 “DC electrical
. If the P89LPC915/916/917 device is to operate
Table 13 “DC electrical characteristics”
P89LPC915/916/917
DD
rise and fall times must be
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
characteristics”), and is
for specifications.
DD
falls below
for
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