Datasheet

MCP23009/MCP23S09

1.6.4 DEFAULT COMPARE REGISTER

FOR INTERRUPT-ON-CHANGE

The default comparison value is configured in the

DEFVAL register. If enabled (via GPINTEN and

INTCON) to compare against the DEFVAL register, an

opposite value on the associated pin will cause an

interrupt to occur.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

DEF7 DEF6 DEF5 DEF4 DEF3 DEF2 DEF1 DEF0

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 DEF7:DEF0: Sets the compare value for pins configured for interrupt-on-change from defaults <7:0>.

Refer to INTCON.

If the associated pin level is the opposite from the register bit, an interrupt occurs.

Refer to INTCON and GPINTEN.