Datasheet

MCP23017/MCP23S17
DS21952B-page 18 © 2007 Microchip Technology Inc.
REGISTER 1-6: IOCON – I/O EXPANDER CONFIGURATION REGISTER (ADDR 0x05)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0
BANK MIRROR
SEQOP DISSLW HAEN ODR INTPOL
—
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 BANK: Controls how the registers are addressed
1 = The registers associated with each port are separated into different banks
0 = The registers are in the same bank (addresses are sequential)
bit 6 MIRROR: INT Pins Mirror bit
1 = The INT pins are internally connected
0 = The INT pins are not connected. INTA is associated with PortA and INTB is associated with PortB
bit 5 SEQOP: Sequential Operation mode bit.
1 = Sequential operation disabled, address pointer does not increment.
0 = Sequential operation enabled, address pointer increments.
bit 4 DISSLW: Slew Rate control bit for SDA output.
1 = Slew rate disabled.
0 = Slew rate enabled.
bit 3 HAEN: Hardware Address Enable bit (MCP23S17 only).
Address pins are always enabled on MCP23017.
1 = Enables the MCP23S17 address pins.
0 = Disables the MCP23S17 address pins.
bit 2 ODR: This bit 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).
bit 1 INTPOL: This bit sets the polarity of the INT output pin.
1 = Active-high.
0 = Active-low.
bit 0 Unimplemented: Read as ‘0’.