PCA8575 查看數據表（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
7. Functional description
Refer to Figure 1 “Block diagram of PCA8575”.
7.1 Device address
Following a START condition, the bus master must send the address of the slave it is
accessing and the operation it wants to perform (read or write). The address of the
PCA8575 is shown in Figure 9. Slave address pins AD2, AD1, and AD0 choose 1 of
8 slave addresses. To conserve power, no internal pull-up resistors are incorporated on
AD2, AD1, and AD0. Address values depending on AD2, AD1, and AD0 can be found in
Table 3 “PCA8575 address map”.
Remark: The General Call address (0000 0000b) and the Device ID address
(1111 100Xb) are reserved and cannot be used as device address. Failure to follow this
requirement will cause the PCA8575 not to acknowledge.
slave address
A6 A5 A4 A3 A2 A1 A0 R/W
Fig 9. PCA8575 address
programmable
002aab636
The last bit of the first byte defines the operation to be performed. When set to logic 1 a
read is selected, while a logic 0 selects a write operation.
When AD2, AD1 and AD0 are held to VDD or VSS, the same address as the PCF8575 is
applied.
7.1.1 Address map
Table 3. PCA8575 address map
A6
A5
A4
A3
A2
A1
A0
Address (hex)
0
1
0
0
0
0
0
20h
0
1
0
0
0
0
1
21h
0
1
0
0
0
1
0
22h
0
1
0
0
0
1
1
23h
0
1
0
0
1
0
0
24h
0
1
0
0
1
0
1
25h
0
1
0
0
1
1
0
26h
0
1
0
0
1
1
1
27h
PCA8575_1
Objective data sheet
Rev. 01 — 30 November 2006
© NXP B.V. 2006. All rights reserved.
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