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4.6.1 Transmission data modulation by IR encoder
When the transmitted data value is 0, a pulse with the width of the baud rate cycle multiplied by 3/16 is output. The
polarity of transmission pulses can be selected by using bit 1 (IR_TXPSEL) of the IRCR0 register.
IRCR (IR_TXPSEL) = 0
UARTx_SOUT
(output)
IRCR (IR_TXPSEL) = 1
4.6.2 Reception data demodulation by IR decoder
The IR decoder outputs 0 if the input pulse width is valid (value set to the PULSE_WIDTH[7:0] bits of IRCR1
register) or longer; otherwise it outputs 1.
(IR_RXPSEL) of the IRCR0 register.
IRCR (IR_RXPSEL) = 0
UARTx_SIN
(input)
IRCR (IR_RXPSEL) = 1
Table 4-2 lists examples of valid pulse width settings (PULSE_WIDTH[7:0] of the IRCR1 register). In this table, the
values of PULSE_WIDTH[7:0] are expressed in decimal notation. This table only presents some examples of the
desired valid reception pulse width and XIN clock frequency values. Change the values according to the user system.
42
CHAPTER 4 DESCRIPTION OF FUNCTIONS
Figure 4-2. Transmission Data Modulation Example
Start
Encoder input
0
Bit time
The polarity of reception pulses can be selected by using bit 5
Figure 4-3. Reception Data Demodulation Example
Bit time
Delay < (3 + PULSE_WIDTH[7:0] value) CLK @ XIN
Start
Decoder output
User's Manual S19262EJ3V0UM
UART frame
Data bit
1
0
1
0
0
1/2 bit time
Pulse width (3/16 bit time)
Pulse width: IRCR1 (PULSE_WIDTH[7:0]) is used to set the
width of pulses to detect as valid pulses.
+ 4/16 bit time
0
1
0
1
0
Data bit
UART frame
Stop
1
1
0
1
Stop
0
1
1
0
1
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