pca9549bs NXP Semiconductors, pca9549bs Datasheet - Page 5

• Manufacturer Part Number: pca9549bs
• Description: Octal Bus Switch With Individually I2c-bus Controlled Enables
• Manufacturer: NXP Semiconductors

Philips Semiconductors
6. Functional description
PCA9549_1
Product data sheet
6.2.1 Control register definition
6.1 Device addressing
6.2 Control register
Following a START condition, the bus master must output the address of the slave it is
accessing. The address of the PCA9549 is shown in
internal pull-up resistors are incorporated on the hardware selectable address pins and
they must be pulled HIGH or LOW.
The last bit of the slave address defines the operation to be performed. When set to
logic 1 a read is selected, while a logic 0 selects a write operation.
Following the successful acknowledgement of the slave address, the bus master will send
a byte to the PCA9549, which will be stored in the Control register. If multiple bytes are
received by the PCA9549, it will save the last byte received. This register can be written
and read via the I
One or several bits are selected by the contents of the Control register. This register is
written after the PCA9549 has been addressed. The entire control byte is used to
determine which bit is to be selected. When a bit is selected to close, the bit will close
after the Acknowledge has been placed on the I
Fig 5. Slave address
Fig 6. Control register
2
C-bus.
Rev. 01 — 11 July 2006
Octal bus switch with individually I
B7
7
1
B6
6
1
fixed
channel selection bits
B5
5
1
(read/write)
B4
4
0
B3
3
A2
selectable
hardware
B2
2
2
C-bus.
A1
B1
1
Figure
A0 R/W
002aaa962
002aab254
B0
0
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
bit 8
5. To conserve power, no
2
C-bus controlled enables
PCA9549
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