The MCP23017, a 16-bit I2C GPIO expander, has always been a tasty chip. With 16 GPIOs addressable over I2C, proper push/pull outputs, software-enabled pull-ups, eight addresses, maskable interrupts ...

“Responding to customer demands, and seizing a market opportunity, Exar now offers GPIO bridging solutions as part of its market leading Interface products,” said Levent Ozcolak, vice president, ...

[Ken Olsen] needed a bunch of analog inputs for his model railroad project. He wanted to use the Raspberry Pi board, but alas there are no analog inputs available on the GPIO header. But there is SPI.