DESCRIPTION
The MK68564 SIO (Serial Input Output) is a dualchannel, multi-function peripheral circuit, designed to satisfy a wide variety of serial data communications requirements in microcomputer systems. Its basicfunction is a serial-to-parallel, parallel-to-serial converter/controller ; however within that role, it is systems software configurable so that its ”personality” may be optimized for any given serial data communications application.

■ COMPATIBLE WITH MK68000 CPU
■ COMPATIBLE WITH MK68000 SERIES DMA’s
■ TWO INDEPENDENT FULL-DUPLEX CHANNELS
■ TWO INDEPENDENT BAUD-RATE GENERATORS
    - Crystal oscillator input
    - Single-phase TTL clock input
■ DIRECTLY ADDRESSABLE REGISTERS (all control registers are read/write)
■ DATA RATE IN SYNCHRONOUS OR ASYNCHRONOUS MODES
    - 0-1.25M bits/second with 5.0MHz system clock rate
■ SELF-TEST CAPABILITY
■ RECEIVE DATA REGISTERS ARE QUADRUPLY BUFFERED ; TRANSMIT REGISTERS ARE DOUBLY BUFFERED
■ DAISY-CHAIN PRIORITY INTERRUPT LOGIC PROVIDES AUTOMATIC INTERRUPT VECTORING WITHOUT EXTERNAL LOGIC
■ MODEM STATUS CAN BE MONITORED
    - Separate modem controls for each channel
■ ASYNCHRONOUS FEATURES
    - 5, 6, 7, or 8 bits/character
    - 1, 11/2, or 2 stop bits
    - Even, odd, or no parity
    - x1, x16, x32, and x64 clock modes
    - Break generation and detection
    - Parity, overrun, and framing error detection
■ BYTE SYNCHRONOUS FEATURES
    - Internal or external character synchronization
    - One or two sync characters in separate registers
    - Automatic sync character insertion
    - CDC-16 or CRC-CCITT block check generation and checking
■ BIT SYNCHRONOUS FEATURES
    - Abort sequence generation and detection
    - Automatic zero insertion and deletion
    - Automatic flag insertion between messages
    - Address field recognition
    - I-field residue handling
    - Valid receive messages protected from overrun
    - CRC-16 or CRC-CCITT block check generation and checking