MCP23017 Datasheet, PDF (22/48 Pages) Microchip Technology – 16-Bit I/O Expander with Serial Interface

MCP23017/MCP23S17
1.6.10 PORT REGISTER
The GPIO register reflects the value on the port.
Reading from this register reads the port. Writing to this
register modifies the Output Latch (OLAT) register.
REGISTER 1-10: GPIO – GENERAL PURPOSE I/O PORT REGISTER (ADDR 0x09)
R/W-0
GP7
bit 7
R/W-0
GP6
R/W-0
GP5
R/W-0
GP4
R/W-0
GP3
R/W-0
GP2
R/W-0
GP1
R/W-0
GP0
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
GP7:GP0: These bits reflect the logic level on the pins <7:0>
1 = Logic-high.
0 = Logic-low.
DS21952B-page 22
© 2007 Microchip Technology Inc.