P89LPC932 Philips Semiconductors, P89LPC932 Datasheet - Page 23

• 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
8.12.4 Input-only configuration
8.12.5 Push-pull output configuration
8.12.6 Port 0 analog functions
8.12.7 Additional port features
8.13.1 Brownout detection
8.13 Power monitoring functions
The input-only port configuration has no output drivers. It is a Schmitt-triggered input
that also has a glitch suppression circuit.
The push-pull output configuration has the same pull-down structure as both the
open-drain and the quasi-bidirectional output modes, but provides a continuous
strong pull-up when the port latch contains a logic ‘1’. The push-pull mode may be
used when more source current is needed from a port output. A push-pull port pin
has a Schmitt-triggered input that also has a glitch suppression circuit.
The P89LPC932 incorporates two Analog Comparators. In order to give the best
analog function performance and to minimize power consumption, pins that are being
used for analog functions must have the digital outputs and digital inputs disabled.
Digital outputs are disabled by putting the port output into the Input-Only (high
impedance) mode.
Digital inputs on Port 0 may be disabled through the use of the PT0AD register,
bits 1:5. On any reset, PT0AD[1:5] defaults to ‘0’s to enable digital functions.
After power-up, all pins are in Input-Only mode. Please note that this is different
from the LPC76x series of devices.
Every output on the P89LPC932 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
specifications.
All ports 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 P89LPC932 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.
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•
After power-up, all I/O pins except P1.5, may be configured by software.
Pin P1.5 is input only. Pins P1.2 and P1.3 and are configurable for either input-only
or open-drain.
Rev. 04 — 06 January 2004
8-bit microcontroller with accelerated two-clock 80C51 core
Table 8 “DC electrical characteristics”
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
P89LPC932
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