p89lpc932ba NXP Semiconductors, p89lpc932ba Datasheet - Page 22

• Manufacturer Part Number: p89lpc932ba
• Description: P89lpc932 8-bit Microcontroller With Accelerated Two-clock 80c51 Core 8 Kb Flash With 512-byte Data Eeprom And 768-byte Ram
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 6:
9397 750 12379
Product data
Clock source
On-chip oscillator or watchdog oscillator
External clock input
Low/medium/high speed oscillator
(external crystal or resonator)
Number of I/O pins available
8.12.1 Port configurations
8.12.2 Quasi-bidirectional output configuration
8.12.3 Open-drain output configuration
8.12 I/O ports
The P89LPC932 has four I/O ports: Port 0, Port 1, Port 2, and Port 3. Ports 0, 1and 2
are 8-bit ports, and Port 3 is a 2-bit port. The exact number of I/O pins available
depends upon the clock and reset options chosen, as shown in
All but three I/O port pins on the P89LPC932 may be configured by software to one of
four types on a bit-by-bit basis. These are: quasi-bidirectional (standard 80C51 port
outputs), push-pull, open drain, and input-only. Two configuration registers for each
port select the output type for each port pin.
P1.5 (RST) can only be an input and cannot be configured.
P1.2 (SCL/T0) and P1.3 (SDA/INT0) may only be configured to be either input-only or
open-drain.
Quasi-bidirectional output type can be used as both an input and output without the
need to reconfigure the port. This is possible because when the port outputs a logic
HIGH, it is weakly driven, allowing an external device to pull the pin LOW. When the
pin is driven LOW, it is driven strongly and able to sink a fairly large current. These
features are somewhat similar to an open-drain output except that there are three
pull-up transistors in the quasi-bidirectional output that serve different purposes.
The P89LPC932 is a 3 V device, but the pins are 5 V-tolerant. In quasi-bidirectional
mode, if a user applies 5 V on the pin, there will be a current flowing from the pin to
V
mode is discouraged.
A quasi-bidirectional port pin has a Schmitt-triggered input that also has a glitch
suppression circuit.
The open-drain output configuration turns off all pull-ups and only drives the
pull-down transistor of the port driver when the port latch contains a logic ‘0’. To be
used as a logic output, a port configured in this manner must have an external
pull-up, typically a resistor tied to V
An open-drain port pin has a Schmitt-triggered input that also has a glitch
suppression circuit.
DD
, causing extra power consumption. Therefore, applying 5 V in quasi-bidirectional
Reset option
No external reset (except during power-up)
External RST pin supported
No external reset (except during power-up)
External RST pin supported
No external reset (except during power-up)
External RST pin supported
Rev. 04 — 06 January 2004
8-bit microcontroller with accelerated two-clock 80C51 core
DD
.
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
P89LPC932
Number of I/O pins
(28-pin package)
26
25
25
24
24
23
Table
6.
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