Datasheet

MC68HC908GP32 Data Sheet, Rev. 10
Freescale Semiconductor 131
Chapter 13
Serial Communications Interface Module (SCI)
13.1 Introduction
This section describes the serial communications interface (SCI) module, which allows high-speed
asynchronous communications with peripheral devices and other MCUs.
13.2 Features
Features of the SCI module include:
• Full-duplex operation
• Standard mark/space non-return-to-zero (NRZ) format
• 32 programmable baud rates
• Programmable 8-bit or 9-bit character length
• Separately enabled transmitter and receiver
• Separate receiver and transmitter CPU interrupt requests
• Programmable transmitter output polarity
• Two receiver wakeup methods:
– Idle line wakeup
– Address mark wakeup
• Interrupt-driven operation with eight interrupt flags:
– Transmitter empty
– Transmission complete
– Receiver full
– Idle receiver input
– Receiver overrun
– Noise error
– Framing error
– Parity error
• Receiver framing error detection
• Hardware parity checking
• 1/16 bit-time noise detection
• Configuration register bit, SCIBDSRC, to allow selection of baud rate clock source
13.3 Pin Name Conventions
The generic names of the SCI I/O pins are:
• RxD (receive data)
• TxD (transmit data)