PCA9549_1

© Koninklijke Philips Electronics N.V. 2006. All rights reserved.

Product data sheet

Rev. 01 — 11 July 2006

6 of 24

Philips Semiconductors

PCA9549

[1]

Several bits can be enabled at the same time. For example, B7 = 0, B6 = 1, B5 = 0, B4 = 0, B3 = 1, B2 = 1,

B1 = 0, B0 = 0, means that bit 8, bit 6, bit 5, bit 2, and bit 1 are disabled and bit 7, bit 4, and bit 3 are

enabled.

6.3 RESET input

The RESET input is an active LOW signal which may be used to recover from a bus fault

6.4 Power-on reset

zeroes causing all the bits to be open (high-impedance state).

The bus switch is optimized at 5.0 V but can operate over the entire supply range with

Table 4.

Control register

Write = channel selection; read = channel status.

B7

B6

B5

B4

B3

B2

B1

B0

Command

XXXXXXX

0

bit 1 disabled

1

bit 1 enabled

XXXXXX

0

X

bit 2 disabled

1

bit 2 enabled

XXXXX

0

XX

bit 3 disabled

1

bit 3 enabled

XXXX

0

XXX

bit 4 disabled

1

bit 4 enabled

XXX

0

XXXX

bit 5 disabled

1

bit 5 enabled

XX

0

XXXXX

bit 6 disabled

1

bit 6 enabled

X

0

XXXXXX

bit 7 disabled

1

bit 7 enabled

0

XXXXXXX

bit 8 disabled

1

bit 8 enabled