The ST16C450 is a universal asynchronous receiver and transmitter. The ST16C450 is an improved version of the NS16450 UART with higher operating speed and lower access time. A programmable baud rate generator is provided to select transmit and receive clock rates from 50 Bps to 1.5 Mbps. The ST16C450 on board status registers provides the error conditions, type and status of the transfer operation being performed. Included is complete MODEM control capability, and a processor interrupt system that may be software tailored to the user's requirements. The ST16C450 provides internal loopback capability for on board diagnostic testing. The ST16C450 is available in 40 pin PDIP, 44 pin PLCC, and 48 pin TQFP packages. It is fabricated in an advanced CMOS process to achieve low drain power and high speed requirements.