Rev. 5.00, 09/03, page 427 of 760
Section 14 Serial Communication Interface (SCI)
14.1 Overview
The SH7709S has an on-chip serial communication interface (SCI) that supports both
asynchronou s and clock sy nchronous serial communication. It also has a multiprocessor
commu n ica tio n f unc ti o n for seri al co mmu nic at ion among two or mor e p ro ces so rs. The SCI
supports a smart card interface, which is a serial communication feature for IC card interfaces that
conforms to the ISO/IEC standard 7816-3 for identification cards. See section 15, Smart Card
Interface, for more information.
14.1.1 Features
Selection of asynchron ous or synchron ous as the serial communi cation mode.
• Asynchronous mode:
Serial data communication is sy n chronized by start-stop in character units. The SCI can
communicate with a universal asynchronous receiver/transmitter (UART), an asynch ronous
communication interface adapter (ACIA), or any other communicat i ons chip that employs
a standard asynchronous serial system. It can also communicate with two or more other
processors using the multiprocesso r communication function. There are 12 selectable serial
data communication formats.
Data length: 7 or 8 bits
Stop bit length: 1 or 2 bits
Parity: Even, odd, or none
Multiprocessor bit: 1 or 0
Receive error detection: Parity, overrun, and framing errors
Break detection: By reading the RxD level directly from the SC port data register (SCPDR)
when a framing error occurs
• Synchr o no us mo d e:
Serial data communication is synchronized with a clock signal. The SCI c an communicate
with other chips having a synchronous communication function. There is one serial data
communication format.
Data length: 8 bits
Receive error detection: Overrun errors
• Full duplex communication: The transmitting and receiving sections are independent, so the
SCI can transmit and receive simultaneously. Both sections use double buffering, so
continuous data transfer is possible in both the transmit and receive directions.
• On-chip baud rate generator with selectable bit rates