HSDL-7002 Lite-On Electronics, HSDL-7002 Datasheet - Page 10

• Manufacturer Part Number: HSDL-7002
• Description: IC ENCODER/DECODER IRDA 16-QFN
• Manufacturer: Lite-On Electronics
• Type: Infrared Encoder/Decoderr

Specifications of HSDL-7002

• Applications: Fax, Modems, Pagers
• Voltage - Supply, Analog: 2.7 V ~ 5.5 V
• Voltage - Supply, Digital: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 516-1702-2

Encoding Scheme
The encoding scheme relies on a clock being present,
which is set to 16 times the data transmission baud rate
(16XCLK). The encoder sends a pulse for every space or
“0” that is sent on the TXD line. On a high to low transition
of the TXD line, the generation of the pulse is delayed for
7 clock cycles of the 16XCLK before the pulse is set high
for 3 clock cycles (or 3/16th of a bit time) and then subse-
quently pulled low. This generates a 3/16th bit time pulse
centered around the bit of information (“0”) that is being
transmitted. For consecutive spaces, pulses with a 1 bit
time delay are generated in series. If a logic “1” (mark) is
sent then the encoder does not generate a pulse.
Figure 8. HSDL-7002 Decoding Scheme
Notes:
1. The stretched pulse must be at least ¾ of a bit time in duration to be correctly interpreted by a UART.
2. It is recommended that the TXD remains high when not transmitting. This ensures the LED is off and will not interfere with signal
10
16XCLK
16XCLK
Figure 7. HSDL-7002 Encoding Scheme
IRRXD
IRTXD
RXD
TXD
reception.
7 CS
16 CYCLES
16 CYCLES
3 CS
16 CYCLES
16 CYCLES
3 CS
16 CYCLES
16 CYCLES
16 CYCLES
16 CYCLES
Decoding Scheme
The IrDA
thought of as a pulse-stretching scheme. Every high to
low transition of the IR_RXD line signifies the arrival of a
pulse. This pulse needs to be stretched to accommodate 1
bit time (or 16 16XCLK cycles). Every pulse that is received
is translated into a “0” or space on the RXD line equal to
1 bit time.

-SIR decoding modulation method can be