I/O Expander, 8Bit, SPI, 18SOIC - 

The MCP23S09-E/SO is a 8-bit I/O Expander with SPI interface operating at 10MHz. The MCP23X09 device provides 8-bit, general purpose parallel I/O expansion for I²C bus or SPI applications. The MCP23X09 consists of multiple 8-bit configuration registers for input, output and polarity selection. The system master enables the I/Os as either inputs or outputs by writing the I/O configuration bits. 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.