MCP23009 Microchip Technology Inc., MCP23009 Datasheet - Page 21

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

1.6.6
The Sequential Operation (SEQOP) controls the
incrementing function of the address pointer. If the
address pointer is disabled, the address pointer does
not automatically increment after each byte is clocked
during a serial transfer. This feature is useful when it is
desired to continuously poll (read) or modify (write) a
register.
The Open-Drain (ODR) control bit enables/disables the
INT pin for open-drain configuration.
REGISTER 1-7:
© 2008 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
U-0
-
CONFIGURATION REGISTER
Unimplemented: Reads as 0
Unimplemented: Reads as 0
SEQOP: Sequential Operation mode bit.
1 = Sequential operation disabled, address pointer does not increment.
0 = Sequential operation enabled, address pointer increments.
Unimplemented: Reads as 0
Unimplemented: Reads as 0
ODR: Configures the INT pin as an open-drain output.
1 = Open-drain output (overrides the INTPOL bit).
0 = Active driver output (INTPOL bit sets the polarity).
INTPOL: Sets the polarity of the INT output pin.
1 = Active-high.
0 = Active-low.
INTCC: Interrupt Clearing Control
1 = Reading INTCAP register clears the interrupt
0 = Reading GPIO register clears the interrupt
U-0
IOCON – I/O EXPANDER CONFIGURATION REGISTER
-
W = Writable bit
‘1’ = Bit is set
SEQOP
R/W-0
U-0
-
‘0’ = Bit is cleared
U = Unimplemented bit, read as ‘0’
MCP23009/MCP23S09
The Interrupt Polarity (INTPOL) sets the polarity of the
INT pin. This bit is functional only when the ODR bit is
cleared, configuring the INT pin as active push-pull.
The Interrupt Clearing Control (INTCC) configures how
interrupts are cleared. When set (INTCC = 1), the
interrupt is cleared when the INTCAP register is read.
When cleared (INTCC = 0), the interrupt is cleared
when the GPIO register is read.
The interrupt can only be cleared when the interrupt
condition is inactive. Refer to Section 1.7.4 “Clearing
Interrupts” for details.
U-0
-
R/W-0
ODR
x = Bit is unknown
INTPOL
R/W-0
DS22121A-page 21
INTCC
R/W-0
bit 0