Datasheet

MCP23018/MCP23S18
DS22103A-page 28 © 2008 Microchip Technology Inc.
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 1-12: GPIO – GENERAL PURPOSE I/O PORT REGISTER
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
GP7 GP6 GP5 GP4 GP3 GP2 GP1 GP0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 GP7:GP0: Reflects the logic level on the pins <7:0>.
1 = Logic-high.
0 = Logic-low.