UPSD33XX Datasheet, PDF (92/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

uPSD33xx
IrDA INTERFACE
uPSD33xx devices provide an internal IrDA inter-
face that will allow the connection of the UART1
serial interface directly to an external infrared
transceiver device. The IrDA interface does this by
automatically shortening the pulses transmitted on
UART1’s TxD1 pin, and stretching the incoming
pulses received on the RxD1 pin. Reference Fig-
ures 36 and 37.
When the IrDA interface is enabled, the output sig-
nal from UART1’s transmitter logic on pin TxD1 is
Figure 36. IrDA Interface
compliant with the IrDA Physical Layer Link Spec-
ification v1.4 (www.irda.org) operating from 1.2k
bps up to 115.2k bps. The pulses received on the
RxD1 pin are stretched by the IrDA interface to be
recognized by UART1’s receiver logic, also adher-
ing to the IrDA specification up to 115.2k bps.
Note: In Figure 37 a logic '0' in the serial data
stream of a UART Frame corresponds to a logic
high pulse in an IR Frame. A logic '1' in a UART
Frame corresponds to no pulse in an IR Frame.
UART1
SIRClk
TxD
RxD
IrDA
Interf ac e
TxD1-IrDA
RxD1-IrDA
IrDA
Transceiver
uPSD33XX
AI07851
Figure 37. Pulse Shaping by the IrDA Interface
Start
Bit
UART Frame
Data Bits
Stop
Bit
0
1
0
1
0
0
1
1
0
1
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Start
Bit
UART Frame
IR Frame
Data Bits
Stop
Bit
0
1
0
1
0
0
1
1
0
1
Bit Time
IR Frame
Pulse Width = 3/16 Bit Time
AI09624