The ST16C452/ST16C452PS (452/452PS) is a dual universal asynchronous receiver and transmitter (UART) with an added bi-directional parallel port that is directly compatible with a CENTRONICS type printer. The parallel port is designed such that the user can configure it as general purpose I/O interface, or for connection to other printer devices. The 452/452PS provides enhanced UART functions, a modem control interface, and data rates up to 1.5Mbps. Onboard status registers provide the user with error indications and operational status. The system interrupts and control may be tailored to meet user requirements. An internal loop-back capability allows onboard diagnostics. A programmable baud rate generator is provided to select transmit and receive clock rates from 50 bps to 1.5 Mbps. The 452/452PS is available in a 68 pin PLCC package. The 452/452PS is compatible with the 16C450. The 452 is available in two versions, the ST16C452 and the ST16C452PS. The ST16C452 provides single hardware pin to control the printer port data direction while the 452PS provides an additionally software control bit to control the printer port data direction to become compatible PS/2 operating system. The 452/452PS is fabricated in an advanced CMOS process with low power consumption.