SH7721 datasheet(704/1524 Pages) RENESAS

704 / 1524 page

Section 19

Infrared Data Association Module (IrDA)

Rev. 3.00 Jan. 18, 2008 Page 642 of 1458

REJ09B0033-0300

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.

SH7721 Datasheet(PDF) 704 Page - Renesas Technology Corp