SH7720 Datasheet, PDF (704/1524 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 19 Infrared Data Association Module (IrDA)
19.4 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.
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.
19.4.1 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 19.2.
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.
19.4.2 Receiving
Received 3/16 IR frame bit-width pulses are demodulated and converted to a UART frame, as
shown in figure 19.2.
Demodulation to 0 is performed for pulse output, and demodulation to 1 is performed for no pulse
output.
Rev. 3.00 Jan. 18, 2008 Page 642 of 1458
REJ09B0033-0300