MCP23S18 Microchip Technology, MCP23S18 Datasheet - Page 31

• Manufacturer Part Number: MCP23S18
• Description: 16-Bit I/O Expander
• Manufacturer: Microchip Technology

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1.7.6
There are two possible configurations to cause
interrupts (configured via INTCON):
1.
2.
See
on interrupt operations.
© 2008 Microchip Technology Inc.
Pins configured for interrupt-on-pin-change
will cause an interrupt to occur if a pin changes
to the opposite state. The default state is reset
after an interrupt occurs. For example, an
interrupt occurs by an input changing from 1 to
0. The new initial state for the pin is a logic 0.
Pins configured for interrupt-on-change from
register value will cause an interrupt to occur if
the corresponding input pin differs from the
register bit. The interrupt condition will remain as
long as the condition exists, regardless if the
INTAP or GPIO is read.
Figure 1-11
INTERRUPT CONDITIONS
and
Figure 1-12
for more information
MCP23018/MCP23S18
FIGURE 1-11:
FIGURE 1-12:
GP:
GP2
INT
Port value
is captured
into INTCAP
GPx
INT
Port value
is captured
into INTCAP
7
X
6
X
ACTIVE
ACTIVE
5
X
INTERRUPT-ON-PIN-
CHANGE
Read GPIO
or INTCAP
INTERRUPT-ON-CHANGE
FROM REGISTER
DEFAULT
DEFVAL
4
X
(INT clears only if interrupt
condition does not exist.)
3
X
Read GPIO
or INTCAP
ACTIVE
2
1
DS22103A-page 31
Port value
is captured
into INTCAP
ACTIVE
1
X
0
X