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TMP91C824
91C824-147
3.9.5
Support for IrDA
SIO0 includes support for the IrDA 1.0 infrared data communication specification.
Figure 3.9.24 shows the block diagram.
Receive data
Transmisison data
IR demodulator
IR modulator
Modem
IR transmitter & LED
IR receiver
SIO0
TMP91C824
TXD0
RXD0
IR output
IR input
Figure 3.9.24 IrDA block diagram
(1) Modulation of the transmission data
When the transfer data is 0, the modem outputs 1 to TXD0 pin with either 3/16 or 1/16 times for
width of baud-rate. The pulse width is selected by the SIRCR<PLSEL>. When the transfer data is 1,
the modem outputs 0.
TXD0 pin
1
0
0
1
1
0
0
Stop
0
Start
Transmission data
Figure 3.9.25 Modulation example of transfer data
(2) Modulation of the receive data
When the receive data has the effective high level pulse width(software selectable), the modem
outputs “0” to SIO0. Otherwise the modem outputs “1” to SIO0. The receive pulse logic is also
selectable by SIRCR<RXSEL>.
Receive data
RXD0 pin
Stop
0
1
0
1
0
1
Start
1
0
Figure 3.9.26 Demodulation example of receive data