HITACHI 341
Section 13 Serial Communication Interface (SCI)
13.1
Overview
The SuperH microcomputer has a serial communication interface (SCI) with two independent
channels. Both channels are functionally identical. The SCI supports both asynchronous and
clocked synchronous serial communication. It also has a multiprocessor communication function
for serial communication among two or more processors.
13.1.1
Features
Asynchronous mode
Serial data communications are synched by start-stop in character units. The SCI can
communicate with a universal asynchronous receiver/transmitter (UART), an asynchronous
communication interface adapter (ACIA), or any other chip that employs a standard
asynchronous serial communication. It can also communicate with two or more other
processors using the multiprocessor communication function. There are twelve selectable
serial data communication formats.
Data length: seven or eight bits
Stop bit length: one or two bits
Parity: even, odd, or none
Multiprocessor bit: one or none
Receive error detection: parity, overrun, and framing errors
Break detection: by reading the RxD level directly when a framing error occurs
Clocked synchronous mode
Serial data communication is synchronized with a clock signal. The SCI can communicate
with other chips having a clocked synchronous communication function. There is one serial
data communication format.
Data length: eight 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
Internal or external transmit/receive clock source: baud rate generator (internal) or SCK pin
(external)
Four types of interrupts: Transmit-data-empty, transmit-end, receive-data-full, and receive-
error interrupts are requested independently. The transmit-data-empty and receive-data-full
interrupts can start the direct memory access controller (DMAC) to transfer data.