HD6417705 Datasheet, PDF (480/739 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

17.4 Operation
The IrDA module can perform infrared communication conforming to IrDA 1.0 by connecting
infrared transmit/receive units. The serial communication interface unit includes a buffer in the
transmit unit and the receive unit, allowing CPU overhead to be reduced and continuous high-
speed communication to be performed.
17.4.1 Overview
The IrDA module modifies IrTx/IrRx transmit/receive data waveforms to satisfy the IrDA 1.0
specification for infrared communication.
In the IrDA 1.0 specification, communication is first performed at a speed of 9600 bps, and the
communication speed is changed. However, the communication rate cannot be automatically
changed in this module, so the communication speed should be confirmed, and the appropriate
speed set for this module by software.
17.4.2 Transmitting
The waveforms of a serial output signal (UART frame) from the SCIF are modified and the signal
is converted into the IR frame serial output signal by the IrDA module, as shown in figure 17.2.
When serial data is 0, a pulse of 3/16 the IR frame bit width is generated and output. When serial
data is 1, no pulse is output.
Rev. 2.00, 09/03, page 434 of 690