The a6850 MegaCore function implements an ACIA, which is a universal asynchronous receiver/transmitter (UART). The a6850 provides an interface between a microprocessor and a serial communications channel. The a6850 receives and transmits data in a variety of configurations, including 7- or 8-bit data words, with odd, even, or no parity, and 1 or 2 stop bits. See Figure 1.