P89LPC9151 NXP [NXP Semiconductors], P89LPC9151 Datasheet - Page 44

• Manufacturer Part Number: P89LPC9151
• Description: 8-bit microcontroller with accelerated two-clock 80C51 core, 2 kB 3 V byte-erasable flash with 8-bit ADC
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
P89LPC9151_61_71_2
Product data sheet
7.15.1.1 Quasi-bidirectional output configuration
7.15.1 Port configurations
7.15 I/O ports
The P89LPC9151 has two I/O ports: Port 0 and Port 1. Ports 0 and 1 are both 6-bit ports.
The P89LPC9161/9171 has three I/O ports: Port 0, Port 1 and Port 2. Ports 0 is 5-bit ports
in the P89LPC9161 and 7-bit ports in the P89LPC9171, Port 1 is 5-bit ports in the
P89LPC9161 and 6-bit ports in the P89LPC9171, Port 2 is 4-bit ports in the P89LPC9161
and 1-bit port in the P89LPC9171. The exact number of I/O pins available depends upon
the clock and reset options chosen, as shown in
Table 13.
[1]
Table 14.
[1]
All but three I/O port pins on the P89LPC9151/9161/9171 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.
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
Clock source
RC oscillator or watchdog
oscillator
External clock input
Clock source
RC oscillator or watchdog
oscillator
External clock input
1. P1.5 (RST) can only be an input and cannot be configured.
2. P1.2 (SCL/T0) and P1.3 (SDA/INT0) may only be configured to be either input-only or
Required for operation above 12 MHz.
Required for operation above 12 MHz.
open-drain.
Number of I/O pins available (P89LPC9151)
Number of I/O pins available (P89LPC9161 and P89LPC9171)
Rev. 02 — 9 February 2010
Reset option
No external reset (except during
power-up)
External RST pin supported
No external reset (except during
power-up)
External RST pin supported
Reset option
No external reset (except during
power-up)
External RST pin supported
No external reset (except during
power-up)
External RST pin supported
P89LPC9151/9161/9171
Table 13
8-bit microcontroller with 8-bit ADC
[1]
[1]
and
Table 14
© NXP B.V. 2010. All rights reserved.
Number of I/O
pins (14-pin
package)
12
11
11
10
Number of I/O
pins (16-pin
package)
14
13
13
12
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