MCS9922 is a single lane multifunction PCI express to I/O controller. It supports two serial ports and eight GPIO's. MCS9922 also provides an option for peripheral expansion through proprietary Cascade interface. The generic cascade interface allows interconnecting with similar chips like MCS9900 to expand the peripheral ports.The serial ports are compatible with RS232, RS422 & RS485 standards and supports throughput from 50bps to 16Mbps. All the GPIO pins are programmable and can be used as Input or Output. An I C interface is provided to configure MCS9922 device options through an external EEPROM.