MCP23009 Datasheet, PDF (17/50 Pages) Microchip Technology – 8-Bit I/O Expander with Open-Drain Outputs

MCP23009/MCP23S09
1.6.2 INPUT POLARITY REGISTER
This register allows the user to configure the polarity on
the corresponding GPIO port bits.
If a bit is set, the corresponding GPIO register bit will
reflect the inverted value on the pin.
REGISTER 1-2: IPOL – INPUT POLARITY PORT REGISTER
R/W-0
IP7
bit 7
R/W-0
IP6
R/W-0
IP5
R/W-0
IP4
R/W-0
IP3
R/W-0
IP2
R/W-0
IP1
R/W-0
IP0
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-0
IP7:IP0: Controls the polarity inversion of the input pins <7:0>
1 = GPIO register bit will reflect the opposite logic state of the input pin
0 = GPIO register bit will reflect the same logic state of the input pin
© 2009 Microchip Technology Inc.
DS22121B-page 17