The PCX857X device family provides 8/16-bit, general purpose parallel I/O expansion for I2C SPI applications. These chips provide simple I/O expansion with reduced bus traffic as they don't take command bytes.
PCX857X devices contain different markings to distinguish features like packaging, bus speed support, and address space. Please review specific datasheet for more information.
PCF8574: https://www.nxp.com/docs/en/data-sheet/PCF8574_PCF8574A.pdf PCF8575: https://www.nxp.com/docs/en/data-sheet/PCF8575.pdf PCA8574: https://www.nxp.com/docs/en/data-sheet/PCA8574_PCA8574A.pdf PCA8575: https://www.nxp.com/docs/en/data-sheet/PCA8575.pdf
This binding includes an Pcx857x abstract base class and derived abstract classes for both 8-bit (Pcx8574) and 16-bit (Pcx8575) variants.
// 0x20 is the device address in this example.
var connectionSettings = new I2cConnectionSettings(1, 0x20);
var i2cDevice = new UnixI2cDevice(connectionSettings);
var pcf8574 = new Pcf8574(i2cDevice);