XR28V384IM48-0A Datasheet, PDF (15/42 Pages) Exar Corporation – 3.3V QUAD LPC UART WITH 128-BYTE FIFO

XR28V384
REV. 1.0.0
3.3V QUAD LPC UART WITH 128-BYTE FIFO
1.4.6 Infrared Mode
The V384 UART Channel A includes the infrared encoder and decoder compatible to IrDA (Infrared Data
Association) version 1.0. The infrared encoder sends out a 3/16 of a bit wide or 1.6 uS HIGH pulse for each “0”
bit in the transmit data stream with a data rate up to 115.2 kbps. This signal encoding reduces the on-time of
the infrared LED, hence reduces the power consumption. See Figure 7.
The infrared encoder and decoder are enabled by setting Infrared Mode Control Register - Read/Write bit-4
to a ’1’. The IRRXA# input assumes an idle level of logic zero after a reset and power up, see Figure 7. The
IRRXA# input will assume an idle level of logic HIGH if bit-0 of the Infrared Mode Control Register - Read/
Write is set to ’1’. The IRTXA# is idle at LOW by default. The IRTXA# will be idle at HIGH if bit-1 of the
Infrared Mode Control Register - Read/Write is set to ’1’.
Typically, the wireless infrared decoder receives the input pulse from the infrared sensing diode on the IRRXA#
pin. Each time it senses a light pulse, it returns a logic 0 to the data bit stream.
FIGURE 7. INFRARED TRANSMIT DATA ENCODING AND RECEIVE DATA DECODING
Character
Data Bits
TX Data 0 ¹ 0 ¹ 0 0 ^{1 1} 0 ¹
Transmit
IR Pulse
(IRTXA#
Pin)
Bit Time _{3/16 Bit Time or 1.6 uS}
1/2 Bit Time
IrEncoder-1
Receive
IR Pulse
(IRRXA#
Pin)
RX Data
Bit Time
1/16 Clock Delay
0 1 0 1 0 0 11 0 1
Data Bits
Character
IRdecoder-1
15