PCA9539A データシートの表示（PDF） - NXP Semiconductors.

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PCA9539A

Low-voltage 16-bit I2C-bus I/O port with interrupt and reset

NXP Semiconductors. 

NXP Semiconductors

PCA9539A

Low voltage 16-bit I2C-bus I/O port with interrupt and reset

6.2 Registers

6.2.1 Pointer register and command byte

Following the successful acknowledgement of the address byte, the bus master sends a

command byte, which is stored in the Pointer register in the PCA9539A. The lower

four bits of this data byte state the operation (read or write) and the internal registers

(Input, Output, Polarity Inversion, or Configuration) that will be affected. This register is

write only.

B7 B6 B5 B4 B3 B2 B1 B0

002aaf540

Fig 5. Pointer register bits

Table 4. Command byte

Pointer register bits

Command byte Register

B7 B6 B5 B4 B3 B2 B1 B0 (hexadecimal)

00000000

00h

Input port 0

00000001

01h

Input port 1

00000010

02h

Output port 0

00000011

03h

Output port 1

00000100

04h

Polarity Inversion port 0

00000101

05h

Polarity Inversion port 1

00000110

06h

Configuration port 0

00000111

07h

Configuration port 1

Protocol

Power-up

default

read byte

read byte

read/write byte

read/write byte

read/write byte

read/write byte

read/write byte

read/write byte

xxxx xxxx[1]

xxxx xxxx

1111 1111

1111 1111

0000 0000

0000 0000

1111 1111

1111 1111

[1] Undefined.

6.2.2 Input port register pair (00h, 01h)

The Input port registers (registers 0 and 1) reflect the incoming logic levels of the pins,

regardless of whether the pin is defined as an input or an output by the Configuration

register. The Input port registers are read only; writes to these registers have no effect.

The default value ‘X’ is determined by the externally applied logic level. An Input port

register read operation is performed as described in Section 7.2 “Reading the port

registers”.

Table 5. Input port 0 register (address 00h)

Bit

7

6

5

4

3

2

1

0

Symbol I0.7

I0.6

I0.5

I0.4

I0.3

I0.2

I0.1

I0.0

Default

X

X

X

X

X

X

X

X

Table 6. Input port 1 register (address 01h)

Bit

7

6

5

4

3

2

1

0

Symbol I1.7

I1.6

I1.5

I1.4

I1.3

I1.2

I1.1

I1.0

Default

X

X

X

X

X

X

X

X

PCA9539A

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 1 — 26 September 2012

© NXP B.V. 2012. All rights reserved.

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