toim5232 Vishay, toim5232 Datasheet - Page 10

• Manufacturer Part Number: toim5232
• Description: Sir Endec For Irda? Applications Integrated Interface Circuit
• Manufacturer: Vishay

TOIM5232
Vishay Semiconductors
TRANSMIT (TXD) CHANNEL
Figure 4 shows the transmission in the default mode. For
data transfer, the endec is set to that mode by BR/D = “0”. In
the examples “6” is always transmitted (binary “00000110”).
The “0” is represented in the IrDA protocol by an optical
pulse. Also here the LSB is transmitted first after the start bit.
“1” is not transmitted.
Channel 1 shows the signal from the RS232 port already
converted to 3 V logic by U1. The Endec encodes that signal
to the RZI IrDA format where a “0” is represented by a pulse.
That is the trace of channel 2. This output is connected the
TXD input of the transceiver and this signal is transmitted as
optical output signal. Channel 3 is the signal for an indicator
lamp connected to the TD_LED driver output. Use 180 
serial resistor to supply voltage for limiting the current
through the LED (not shown in the circuit diagram).
When using the (not recommended) 3/16-bit pulse width the
oscillogram looks like figure 5.
The transmission with the highest SIR bit rate of 115.2 bit/s
looks like what is shown in figure 6. However, the horizontal
time scale is different.
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10
Fig. 4 - Data transmission with 9.6 kbit/s,1.627 µs pulse duration
1->
2->
3->
1->
2->
3->
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Fig. 5 - Data transmission with the setting 9.6 kbit/s,
1) Ch1: TD_232 inp. pin 4, vertical scale: 2 V/div., horizontal scale: 200 µs/div.
2) Ch2: TD_IR, pin 14; 1.6 µs pulse duration
3) Ch3: TD_LED, pin 9
1) Ch1: TD_232, pin 4, vertical scale: 2 V/div., horizontal scale: 200 µs/div.
2) Ch2: TD_IR, pin 14; 3/16 bit pulse duration
3) Ch3: TD_LED, pin 9
STA 0
T
3/16 bit pulse duration (19.5 µs)
1
1
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0
For technical questions within your region, please contact one of the following:
0
0
0
0
SIR Endec for IrDA
Integrated Interface Circuit
®
RECEIVE (RXD) CHANNEL
In the default 9600 bit/s mode the signals will look like those
shown in figure 7 and figure 8.
The endec stretches the received pulses of about 2 µs
duration from the transceiver output (figure 7, channel 1)
independent of the pulse duration to the full bit width
generating NRZ code (channel 2). Channel 3 is the signal for
the indicator lamp.
As shown in figure 8, channels 2 and 3, the final NRZ signal
is identical to figure 7, even when longer pulses are received.
In the 115.2 kbit/s mode the signals will look like those shown
Fig. 6 - Data transmission with the setting 115.2 kbit/s, 1.627 µs
Applications
1->
pulse duration. By definition, the pulse duration of 1.627 µs is
2->
3->
1->
2->
3->
1->
2->
3->
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Fig. 7 - Data reception with the setting 9.6 kbit/s.
Fig. 8 - Data reception with the setting 9.6 kbit/s.
1) Ch1: TD_232, pin 4, vertical scale: 2 V/div., horizontal scale: 20 µs/div.
2) Ch2: TD_IR, pin 14; 1.6 µs pulse duration
3) Ch3: TD_LED, pin 9
1) Ch1: TOIM4232; RD_IR, pin 15, vertical scale: 2 V/div.,
2) Ch2: TOIM4232; RD_232, pin 3
3) Ch3: TOIM4232; RD_LED, pin 10
1) Ch1: TOIM4232; RD_IR, pin 15, vertical scale: 2 V/div.,
2) Ch2: TOIM4232; RD_232, pin 3
3) Ch3: TOIM4232; RD_LED, pin 10
Same as in figure 7, extended pulse duration
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horizontal scale: 200 µs/div.
horizontal scale: 200 µs/div.
identical to the 3/16-bit pulse width.
Short RXD pulse
Document Number: 81749
Rev. 1.2, 17-Nov-10