MC908AP32CFBE Datasheet, PDF (155/324 Pages) Freescale Semiconductor, Inc – The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate location.

Chapter 11
Serial Communications Interface Module (SCI)
11.1 Introduction
The MC68HC908AP64 has two SCI modules:
• SCI1 is a standard SCI module, and
• SCI2 is an infrared SCI module.
This section describes SCI1, the serial communications interface (SCI) module, which allows high-speed
asynchronous communications with peripheral devices and other MCUs.
NOTE
When the SCI is enabled, the TxD pin is an open-drain output and requires
a pullup resistor to be connected for proper SCI operation.
11.2 Features
Features of the SCI module include the following:
• 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
MC68HC908AP Family Data Sheet, Rev. 4
Freescale Semiconductor
155