MCP23009 Microchip Technology Inc., MCP23009 Datasheet - Page 19

• Manufacturer Part Number: MCP23009
• Description: 8-bit I/o Expander With Open-drain Outputs
• Manufacturer: Microchip Technology Inc.

1.6.4
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.
REGISTER 1-5:
© 2008 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7-0
R/W-0
DEF7
DEFAULT COMPARE REGISTER
FOR INTERRUPT-ON-CHANGE
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.
R/W-0
DEF6
DEFVAL – DEFAULT VALUE REGISTER
W = Writable bit
‘1’ = Bit is set
R/W-0
DEF5
R/W-0
DEF4
‘0’ = Bit is cleared
U = Unimplemented bit, read as ‘0’
MCP23009/MCP23S09
R/W-0
DEF3
R/W-0
DEF2
x = Bit is unknown
R/W-0
DEF1
DS22121A-page 19
R/W-0
DEF0
bit 0