P87CL881H View Datasheet(PDF) - Philips Electronics

Part Name

Description

Manufacturer

P87CL881H

Low-voltage microcontroller with 63-kbyte OTP program memory and 2-kbyte RAM / LQFP44 Package

Philips Electronics 

Philips Semiconductors

Low-voltage microcontroller with 63-kbyte

OTP program memory and 2-kbyte RAM

Product specification

P87CL881H

Mode 1 Standard port; quasi-bidirectional I/O with

pull-up. The strong pull-up p1 is turned on for

only one oscillator periods after a LOW-to-HIGH

transition in the port latch. After these two

oscillator periods the port is only weakly driven

through p2 and ‘very weakly’ driven through p3.

See Fig.3b.

Mode 2 High-impedance; this mode turns all port output

drivers off. Thus, the pin will not source or sink

current and may be used as an input-only pin with

no internal drivers for an external device to

overcome. See Fig.3c.

Mode 3 Push-pull; output with drive capability in both

polarities. In this mode, pins can only be used as

outputs. See Fig.3d.

Tables 2 and 3 show the configuration register settings for

the four output configurations. The electrical

characteristics of each output configuration are specified

in Chapter 8. The default port configuration after reset is

given in Table 2.

In case of external memory access, the appropriate

options for ports P0, P2 and P3.6/P3.7 (WR/RD, only in

case of external data memory access) must be set by

software.

For Special Function Registers for port configurations/data

please refer to Table 2, note 1.

Table 3 Port configuration register settings

MODE(1)

0

1

2

3

PnCFGA

0

1

0

1

PnCFGB

PORT OUTPUT CONFIGURATION

NORMAL PORTS

I2C-BUS PORTS (P1.6 AND P1.7)

0

open-drain

open-drain

0

quasi-bidirectional

open-drain

1

high-impedance

high-impedance

1

push-pull

open-drain

Note

1. Mode changes may cause glitches to occur during transitions. When modifying both registers, write instructions

should be carried out consecutively.

1999 Apr 16

11

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