This 1MHz Asynchronous Communications Interface Adapter (ACIA) facilitates the formatting and control of data for serial asynchronous communication, enabling integration with bus-organized systems like the MC6800 Microprocessing Unit.

Equipped with select, enable, read/write, interrupt, and bus interface logic, it facilitates bidirectional data transfer over an 8-bit data bus. The ACIA serially transmits and receives parallel data from the bus system, ensuring proper formatting and error checking. Its functional setup is configurable via the data bus during system initialization. A programmable Control Register allows customization of word lengths, clock division ratios, transmit and receive control, and interrupt control. Additionally, it offers three control lines for direct interfacing with peripherals or modems like the MC6860L 0-600 bps digital modem.