MC68HC705C9A Datasheet, PDF (59/118 Pages) Motorola, Inc – Microcontrollers

Chapter 9
Serial Communications Interface (SCI)
9.1 Introduction
This section describes the on-chip asynchronous serial communications interface (SCI). The SCI allows
full-duplex, asynchronous, RS232 or RS422 serial communication between the MCU and remote devices,
including other MCUs. The transmitter and receiver of the SCI operate independently, although they use
the same baud rate generator.
9.2 Features
Features of the SCI include:
• Standard mark/space non-return-to-zero format
• Full-duplex operation
• 32 programmable baud rates
• Programmable 8-bit or 9-bit character length
• Separately enabled transmitter and receiver
• Two receiver wakeup methods:
– Idle line wakeup
– Address mark wakeup
• Interrupt-driven operation capability with five interrupt flags:
– Transmitter data register empty
– Transmission complete
– Transmission data register full
– Receiver overrun
– Idle receiver input
• Receiver framing error detection
• 1/16 bit-time noise detection
9.3 SCI Receiver Features
Features of the SCI receiver include:
• Receiver wakeup function (idle line or address bit)
• Idle line detection
• Framing error detection
• Noise detection
• Overrun detection
• Receiver data register full flag
MC68HC05C9A Advance Information Data Sheet, Rev. 4.1
Freescale Semiconductor
59