MCP23S17 Microchip Technology, MCP23S17 Datasheet - Page 3

• Manufacturer Part Number: MCP23S17
• Description: 16-Bit I/O Expander with Serial Interface
• Manufacturer: Microchip Technology

1.0
The
family provides 16-bit, general purpose parallel I/O
expansion for I
devices differ only in the serial interface.
• MCP23017 – I
• MCP23S17 – SPI interface
The MCP23X17 consists of multiple 8-bit configuration
registers for input, output and polarity selection. The
system master can enable the I/Os as either inputs or
outputs by writing the I/O configuration bits (IODIRA/B).
The data for each input or output is kept in the
corresponding input or output register. The polarity of
the Input Port register can be inverted with the Polarity
Inversion register. All registers can be read by the
system master.
The 16-bit I/O port functionally consists of two 8-bit
ports (PORTA and PORTB). The MCP23X17 can be
configured to operate in the 8-bit or 16-bit modes via
IOCON.BANK.
© 2007 Microchip Technology Inc.
MCP23017/MCP23S17
DEVICE OVERVIEW
2
2
C bus or SPI applications. The two
C interface
(MCP23X17)
device
MCP23017/MCP23S17
There are two interrupt pins, INTA and INTB, that can
be associated with their respective ports, or can be
logically OR’ed together so that both pins will activate if
either port causes an interrupt.
The interrupt output can be configured to activate
under two conditions (mutually exclusive):
1.
2.
The Interrupt Capture register captures port values at
the time of the interrupt, thereby saving the condition
that caused the interrupt.
The Power-on Reset (POR) sets the registers to their
default values and initializes the device state machine.
The hardware address pins are used to determine the
device address.
When
corresponding Input Port register state. This is
used to indicate to the system master that an
input state has changed.
When an input state differs from a preconfigured
register value (DEFVAL register).
any
input
state
differs
DS21952B-page 3
from
its