pca9546abs NXP Semiconductors, pca9546abs Datasheet - Page 6

• Manufacturer Part Number: pca9546abs
• Description: 4-channel I2c Switch With Reset
• Manufacturer: NXP Semiconductors

Philips Semiconductors
PCA9546A_4
Product data sheet
6.2.1 Control register definition
6.2 Control register
Following the successful acknowledgement of the slave address, the bus master will send
a byte to the PCA9546A, which will be stored in the control register. If multiple bytes are
received by the PCA9546A, it will save the last byte received. This register can be written
and read via the I
One or several SCx/SDx downstream pair, or channel, is selected by the contents of the
control register. This register is written after the PCA9546A has been addressed. The
4 LSBs of the control byte are used to determine which channel is to be selected. When a
channel is selected, the channel will become active after a STOP condition has been
placed on the I
the channel is made active, so that no false conditions are generated at the time of
connection.
Table 4.
Remark: Several channels can be enabled at the same time. Example: B3 = 0, B2 = 1,
B1 = 1, B0 = 0, means that channel 0 and channel 3 are disabled and channel 1 and
channel 2 are enabled. Care should be taken not to exceed the maximum bus
capacitance.
D7
X
X
X
X
0
Fig 6. Control register
D6
X
X
X
X
0
Control register: Write—channel selection; Read—channel status
2
D5
X
X
X
X
0
C-bus. This ensures that all SCx/SDx lines will be in a HIGH state when
2
C-bus.
Rev. 04 — 29 August 2006
D4
X
X
X
X
0
X
7
X
6
B3
X
X
X
0
1
0
5
X
X
4
B2
X
X
0
1
X
0
channel selection bits
B3
3
(read/write)
B2
2
B1
X
0
1
X
X
0
B1
1
4-channel I
B0
0
B0
0
1
X
X
X
0
002aab190
channel 0
channel 1
channel 2
channel 3
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Command
channel 0 disabled
channel 0 enabled
channel 1 disabled
channel 1 enabled
channel 2 disabled
channel 2 enabled
channel 3 disabled
channel 3 enabled
no channel selected;
power-up/reset default state
2
C-bus switch with reset
PCA9546A
6 of 25