MCP23008-E/P Microchip Technology, MCP23008-E/P Datasheet - Page 21

• Manufacturer Part Number: MCP23008-E/P
• Description: IC I/O EXPANDER I2C 8B 18DIP
• Manufacturer: Microchip Technology

Specifications of MCP23008-E/P

• Package / Case: 18-DIP (0.300", 7.62mm)
• Interface: I²C
• Number Of I /o: 8
• Interrupt Output: Yes
• Frequency - Clock: 1.7MHz
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Includes: POR
• Logic Family: MCP23008
• Propagation Delay Time: 50 ns
• Operating Supply Voltage: 1.8 V to 5.5 V
• Power Dissipation: 700 mW
• Operating Temperature Range: - 40 C to + 125 C
• Input Voltage: 1.8 V to 5.5 V
• Logic Type: I/O Expander
• Maximum Clock Frequency: 10 MHz
• Maximum Operating Frequency: 1.7 MHz
• Mounting Style: Through Hole
• Output Current: 25 mA
• Output Voltage: 1.8 V to 4.5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: GPIODM-KPLCD - BOARD DEMO LCD GPIO EXP KEYPAD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

1.7
The interrupt output pin will activate if an internal
interrupt occurs. The interrupt block is configured by
the following registers:
• GPINTEN – enables the individual inputs
• DEFVAL – holds the values that are compared
• INTCON – controls if the input values are
• IOCON (ODR and INPOL) – configures the INT
Only pins configured as inputs can cause interrupts.
Pins configured as outputs have no affect on INT.
Interrupt activity on the port will cause the port value to
be captured and copied into INTCAP. The interrupt will
remain active until the INTCAP or GPIO register is
read. Writing to these registers will not affect the
interrupt.
The first interrupt event will cause the port contents to
be copied into the INTCAP register. Subsequent
interrupt conditions on the port will not cause an
interrupt to occur as long as the interrupt is not cleared
by a read of INTCAP or GPIO.
1.7.1
There are two possible configurations to cause
interrupts (configured via INTCON):
1.
2.
See Figure 1-6 and Figure 1-7 for more information on
interrupt operations.
© 2007 Microchip Technology Inc.
against the associated input port values
compared against DEFVAL or the previous values
on the port
pin as push-pull, open-drain and active-level
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.
Interrupt Logic
INTERRUPT CONDITIONS
MCP23008/MCP23S08
FIGURE 1-6:
FIGURE 1-7:
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 GPIU
or INTCAP
INTERRUPT-ON-CHANGE
FROM REGISTER
DEFAULT
DEFVAL
4
X
(INT clears only if interrupt
condition does not exist.)
3
X
Read GPIU
or INTCAP
ACTIVE
2
0
DS21919E-page 21
Port value
is captured
into INTCAP
ACTIVE
1
X
0
X