PCA8575 データシートの表示（PDF） - Philips Electronics
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PCA8575 Datasheet PDF : 30 Pages
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NXP Semiconductors
PCA8575
Remote 16-bit I/O expander for I2C-bus with interrupt
10. Application design-in information
10.1 Bidirectional I/O expander applications
In the 8-bit I/O expander application shown in Figure 19, P00 and P01 are inputs, and P02
to P07 are outputs. When used in this configuration, during a write, the input (P00 and
P01) must be written as HIGH so the external devices fully control the input ports. The
desired HIGH or LOW logic levels may be written to the I/Os used as outputs (P02 to
P07). During a read, the logic levels of the external devices driving the input ports (P00
and P01) and the previous written logic level to the output ports (P02 to P07) will be read.
The GPIO also has an interrupt line (INT) that can be connected to the interrupt logic of
the microprocessor. By sending an interrupt signal on this line, the remote I/O informs the
microprocessor that there is incoming data or a change of data on its ports without having
to communicate via the I2C-bus.
VDD
VDD
VDD
CORE
PROCESSOR
SDA
SCL
INT
AD0
AD1
AD2
P00
temperature sensor
P01
battery status
P02
control for latch
P03
control for switch
P04
control for audio
P05
control for camera
P06
control for MP3
P07
Fig 19. Bidirectional I/O expander application
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10.2 High current-drive load applications
The GPIO has a maximum sinking current of 25 mA per bit. In applications requiring
additional drive, two port pins in the same octal may be connected together to sink up to
50 mA current. Both bits must then always be turned on or off together. Up to 8 pins (one
octal) can be connected together to drive 200 mA.
VDD
CORE
PROCESSOR
VDD
SDA
P00
SCL
P01
INT
P02
P03
P04
AD0
P05
AD1
P06
AD2
P07
Fig 20. High current-drive load application
VDD
LOAD
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PCA8575_1
Objective data sheet
Rev. 01 — 30 November 2006
© NXP B.V. 2006. All rights reserved.
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