pca9541a NXP Semiconductors, pca9541a Datasheet - Page 26

• Manufacturer Part Number: pca9541a
• Description: 2-to-1 I2c-bus Master Selector With Interrupt Logic And Reset
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9541A_3
Product data sheet
10.3 Masters with shared resources
10.4 Gatekeeper multiplexer
Some masters may not be multi-master capable or some masters may not work well
together and continually lock up the bus. The PCA9541A can be used to separate the
masters, as shown in
Field Replaceable Unit (FRU) EEPROMs or temperature sensors.
The PCA9541A/03 can act as a gatekeeper multiplexer in applications where there are
multiple I
address of ‘Z’ as shown in
I
master by using one PCA9541A/03 per card/device. Since each PCA9541A/03 has its
own unique address (for example, ‘A’, ‘B’, ‘C’, and so on), the EEPROMs can be
connected to the master, one at a time, by connecting one PCA9541A/03 (Master 0
position) while keeping the rest of the cards/devices isolated (off position).
The alternative, shown with dashed lines, is to use a PCA9548 1-to-8 channel switch on
the master card and run 8 I
master to each card. The number of card pins used is the same in either case, but there
are 7 less pairs of SDA/SCL traces on the printed-circuit board if the PCA9541A/03 is
used.
2
Fig 20. Masters with shared resources application
C-bus. Up to 16 hot swappable cards/devices can be multiplexed to the same bus
2
C-bus devices with the same fixed address (for example, EEPROMs with
MASTER
MAIN
Figure
Rev. 03 — 16 July 2009
2-to-1 I
Figure
2
C-bus devices, one to each EEPROM card, to multiplex the
20, but still allow shared access to slave devices, such as
PCA9541A
PCA9541A
SLAVE A0
SLAVE B0
2
21) connected in a multipoint arrangement to the same
C-bus master selector with interrupt logic and reset
ASSEMBLY A
ASSEMBLY B
SLAVE A1
SLAVE B1
SLAVE A2
SLAVE B2
SDA/SCL
SDA/SCL
PCA9541A
MASTER A
MASTER B
© NXP B.V. 2009. All rights reserved.
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