INS8250

INS8250/INS8250-B National Sem iconductor INS8250, INS8250-B Universal Asynchronous Receiver/Transmitter General Description Each of these parts function as a serial data input/output interface in a microcomputer system. The system software determines the functional configuration of the UART via a TRI-STATE® 8-bit bidirectional data bus. The UART performs serial-to-parallel conversion on data characters received from a peripheral device or a MODEM, and parallel-to-serial conversion on data characters re­ ceived from the CPU. The CPU can read the complete status of the UART. Status information reported includes the type and condition of the transfer operations being per­ formed by the UART, as well as any error conditions (parity, overrun, framing, or break interrupt). The UART includes a programmable baud rate generator that is capable of dividing the timing reference clock input by divisors of 1 to (216-1 ), and producing a 16 X clock for driving the internal transmitter logic. Provisions are also in­ cluded to use this 16 x clock to drive the receiver logic. The UART includes a complete MODEM-control capability and a processor-interrupt system. Interrupts can be programmed to the user’s requirements minimizing the computing re­ quired to handle the communications link. National’s INS8250 universal asynchronous receiver trans­ mitter (UART) is the unanimous choice of almost every PC and add-on manufacturer in the world. The INS8250 is a programmable communications chip av...