Embedded Technologies, Inc.

8251 Serial Controller


8251 Serial Controller is an USART with support for asynchronous communication only. This controller converts parallel data from the processor to serial data and transmits it and converts the serial received data into parallel data for the processor to read.

Product Specifications
  • RS-232-C protocol support
  • Baud rate generator or timer output selectable as Tx/Rx clock
  • Asynchronous communication only
  • Serial interrupt support
  • Clock rates of baud rate of x16 or x64
  • Character length of 7 or 8 bits
  • 1 or 2 Stop bits
  • Break transmission
  • Automatic break detection
  • Full duplex double buffer system
  • Parity addition/checking
  • Error detection for parity, overrun and framing errors


  • Compatible with 8251 and uPD71051
  • Programmable baud rate generator