2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port I/O Expander

14

______________________________________________________________________________________

COMMAND ADDRESS

REGISTER

D15

D14

D13

D12

D11

D10

D9

D8

HEX

CODE

Port 26 only

X

0

1

1

1

0

1

0

0x3A

Port 27 only

X

0

1

1

1

0

1

1

0x3B

Port 28 only

X

0

1

1

1

1

0

0

0x3C

Port 29 only

X

0

1

1

1

1

0

1

0x3D

Port 30 only

X

0

1

1

1

1

1

0

0x3E

Port 31 only

X

0

1

1

1

1

1

1

0x3F

4 ports 4–7 (data bits D0–D3)

X

1

0

0

0

0

0

0

0x40

5 ports 4–8 (data bits D0–D4)

X

1

0

0

0

0

0

1

0x41

6 ports 4–9 (data bits D0–D5)

X

1

0

0

0

0

1

0

0x42

7 ports 4–10 (data bits D0–D6)

X

1

0

0

0

0

1

1

0x43

8 ports 4–11

X

1

0

0

0

1

0

0

0x44

8 ports 5–12

X

1

0

0

0

1

0

1

0x45

8 ports 6–13

X

1

0

0

0

1

1

0

0x46

8 ports 7–14

X

1

0

0

0

1

1

1

0x47

8 ports 8–15

X

1

0

0

1

0

0

0

0x48

8 ports 9–16

X

1

0

0

1

0

0

1

0x49

8 ports 10–17

X

1

0

0

1

0

1

0

0x4A

8 ports 11–18

X

1

0

0

1

0

1

1

0x4B

8 ports 12–19

X

1

0

0

1

1

0

0

0x4C

8 ports 13–20

X

1

0

0

1

1

0

1

0x4D

8 ports 14–21

X

1

0

0

1

1

1

0

0x4E

8 ports 15–22

X

1

0

0

1

1

1

1

0x4F

8 ports 16–23

X

1

0

1

0

0

0

0

0x50

8 ports 17–24

X

1

0

1

0

0

0

1

0x51

8 ports 18–25

X

1

0

1

0

0

1

0

0x52

8 ports 19–26

X

1

0

1

0

0

1

1

0x53

8 ports 20–27

X

1

0

1

0

1

0

0

0x54

8 ports 21–28

X

1

0

1

0

1

0

1

0x55

8 ports 22–29

X

1

0

1

0

1

1

0

0x56

8 ports 23–30

X

1

0

1

0

1

1

1

0x57

8 ports 24–31

X

1

0

1

1

0

0

0

0x58

7 ports 25–31

X

1

0

1

1

0

0

1

0x59

6 ports 26–31

X

1

0

1

1

0

1

0

0x5A

5 ports 27–31

X

1

0

1

1

0

1

1

0x5B

4 ports 28–31

X

1

0

1

1

1

0

0

0x5C

3 ports 29–31

X

1

0

1

1

1

0

1

0x5D

2 ports 30–31

X

1

0

1

1

1

1

0

0x5E

1 port 31 only

X

1

0

1

1

1

1

1

0x5F

Table 5. Register Address Map (continued)

Note: Unused bits read as zero.