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

28-Port I/O Expander

16

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Table 7. Configuration Register Format

REGISTER DATA

FUNCTION

ADDRESS CODE

(HEX)

D7

D6

D5

D4

D3

D2

D1

D0

Configuration Register

0x04

M

0

XXXXXS

Table 8. Shutdown Control (S Data Bit D0) Format

REGISTER DATA

FUNCTION

ADDRESS CODE

(HEX)

D7

D6

D5

D4

D3

D2

D1

D0

Shutdown

0x04

M

0

XXXXX

0

Normal Operation

0x04

M

0

XXXXX

1

Table 9. Transition Detection Control (M Data Bit D7) Format

REGISTER DATA

FUNCTION

ADDRESS CODE

(HEX)

D7

D6

D5

D4

D3

D2

D1

D0

Disabled

0x04

0

0

XXXXXS

Enabled

0x04

1

0

XXXXXS

Table 10. Transition Detection Mask Register

REGISTER DATA

FUNCTION

REGISTER

ADDRESS

(HEX)

READ/

WRITE

D7

D6

D5

D4

D3

D2

D1

D0

Read

IRQ Status*

Mask

Register

0x06

Write

Unchanged

Port

30

mask

Port

29

mask

Port

28

mask

Port

27

mask

Port

26

mask

Port

25

mask

Port

24

mask

*IRQ is automatically cleared after it is read.