HD64F2149YV datasheet(512/1075 Pages) RENESAS

512 / 1075 page

Section 15 Serial Communication Interface (SCI, IrDA)

Rev. 3.00 Jan 18, 2006 page 484 of 1044

REJ09B0280-0300

15.3.5

IrDA Operation

Figure 15.21 shows a block diagram of the IrDA function.

When the IrDA function is enabled with bit IrE in KBCOMP, the SCI channel 2 TxD2 and RxD2

signals are subjected to waveform encoding/decoding conforming to IrDA specification version

1.0 (IrTxD and IrRxD pins). By connecting these pins to an infrared transceiver/receiver, it is

possible to implement infrared transmission/reception conforming to the IrDA specification

version 1.0 system.

In the IrDA specification version 1.0 system, communication is started at a transfer rate of 9600

bps, and subsequently the transfer rate can be varied as necessary. As the IrDA interface in the

H8S/2169 or H8S/2149 does not include a function for varying the transfer rate automatically, the

transfer rate setting must be changed by software.

IrDA

Pulse encoder

Pulse decoder

KBCOMP

TxD2/IrTxD

RxD2/IrRxD

SCI2

TxD

RxD

Figure 15.21 Block Diagram of IrDA Function

Transmission: In transmission, the output signal (UART frame) from the SCI is converted to an

IR frame by the IrDA interface (see figure 15.22).

When the serial data is 0, a high-level pulses of 3/16 the bit rate (interval equivalent to the width

of one bit) is output (initial value). The high-level pulse can be varied according to the setting of

bits IrCKS2 to IrCKS0 in KBCOMP.

The high-level pulse width is fixed at a minimum of 1.41 µs, and a maximum of (3/16 + 2.5%)

bit rate or (3/16

× bit rate) + 1.08 µs.

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