SIR Endec for IrDA Applications
Integrated Interface Circuit
Description
The TOIM4232 Endec IC provides proper pulse shaping for the SIR IrDA
as of the 4000-series. For transmitting the TOIM4232
shortens the RS232 output signal to IrDA compatible
electrical pulses to drive the infrared transmitter. In
the receive mode, the TOIM4232 stretches the
received infrared pulses to the proper bit width
depending on the operating bit rate. The IrDA bit rate
varies from 2.4 kbit/s to 115.2 kbit/s.The TOIM4232 is
using a crystal clock 3.6864 MHz for its pulse stretching and shortening. The clock can be generated by
the internal oscillator. An external clock can be used,
too. The TOIM4232 is programmable to operate from
1200 bit/s to 115.2 kbit/s by the communication software through the RS232 port. The output pulses are
software programmable as either 1.627 µs or 3/16 of
bit time. The typical power consumption is very low
with about 10 mW in operational state and in the order
of a few microwatts in standby mode.
ULC Technology: High performance gate array
package using multiple metal layer CMOS technology
featuring sub-micron channel lengths (0.35 µm).
®
front end infrared transceivers
TOIM4232
Vishay Semiconductors
18080
Features
• Pulse shaping function (shortening
and stretching) used in SIR IrDA
applications
• Directly interfaces the SIR transceiver
TFD..- and TFB..- series to an RS232 port
• Programmable baud clock generator (1200 Hz to
115.2 kHz), 13 baud rates
• 3/16 bit pulse duration or 1.627 µs pulse selectable
• SO16 - package
• 2.7 V to 3.6 V operation voltage, 5 V tolerant inputs
• Low operating current
• Lead (Pb)-free device
• Device in accordance to RoHS 2002/95/EC and
WEEE 2002/96EC
®
e3
Ordering Information
Part NumberQty / Reel
TOIM4232-TR1500 pcs
Block Diagram
Document Number 82546
Rev. 1.4, 07-Dec-05
TD_232
RD_232
BR/D
RESET
GND
Vcc
Endec
Baud
Generator
Logic
Osci llator
X1
TD_IR
RD_IR
TD_LED
RD_LED
S1
S2
Vcc_SD
X2
18079
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1
TOIM4232
Vishay Semiconductors
Pin Assignment and Description
Pin NumberSymbolDescriptionI/OActive
1RESETResets all internal registers. Initially must be HIGH ("1") to reset internal
registers. When HIGH, the TOIM4232 sets the IrDA default bit rate of 9600
bit/s, sets pulse width to 1.627 µs. The V
reset signal which allows to shut down of a TFDx4x00 transceiver when
applying the reset signal to the TOIM4232. When using devices with
external SD like TFDS4203, the reset line can be used directly as shut
down signal. RESET pin can be controlled by either the RTS or DTR line
through RS232 level converter. Minimum hold time for resetting is 1 µs.
Disables the oscillator when active.
2BR/ DBaud Rate control/ Data.
BR/ D = 0, data communication mode:
RS232 TXD data line is connected (via a level shifter) to TD_232 input pin.
The TXD - signal is appropriately shortened and applied to the output
TD_IR, driving the TXD input of the IR transceiver. The RXD line of the
transceiver is connected to the RD_IR input. This signal is stretched to the
correct bit length according the programmed bit rate and is routed to the
RS232 RXD line at the RD_232 pin.
Data received from the RS232 port is interpreted as Control Word. The
Control Word programs the baud rate width will be effective as soon as BR/
3RD_232Received signal data output of stretched signal to the RS232 RXD line
4TD_232Input of the signal to be transmitted from the RS232 port TXD line (passing
8GNDGround in common with the RS232 port and IrDA transceiver ground
9TD_LEDTransmit LED indicator driver. Use 180 Ω current limiting resistor in.series
10RD_LEDReceive LED indicator driver. Use 180 Ω current limiting resistor in series
11NCNo connection
12S1User Programmable Bit. Can be used to turn ON/ OFF a front-end infrared
13S2User Programmable Bit. Can be used to turn ON/ OFF a front-end infrared
14TD_IRData output of shortened signal to the infrared transceiverOHIGH
15RD_IRData input from the infrared transceiver, min. pulse duration 1.63 µs **)ILOW
16VCCSupply voltageI
*) Crystal should be connected as shown in figure 2. In addition connect a 100 kΩ resistor from Pin 6 to Pin 7 and from Pin 6 and Pin 7 a
22 pF capacitor to ground, respectively. When an external clock is available connect it to Pin 6 leaving Pin 7 open. The external resistor
of 100 kΩ is used to accelerate the start of oscillation after reset or power - on. The value depends on the "Q" of the resonator. With low
Q resonators it is not necessary. The start - up time of the oscillator is between 30 µs (with piezo resonators) and above 2 ms with high Q
quartzes.
**) All Vishay Semiconductor SIR transceivers fulfill this condition
_SDOutputs an inverted RESET signal. Can be used to shut down the power
CC
supply of a 4000 series transceiver (e.g., TFDU4100). V
output function. This pin can be used to shut down a transceiver (e.g.,
TFDx4xxx). Output polarity: Inverted RESET input.
transceiver (e.g., an infrared module at the adapter front)
transceiver (e.g., an infrared module at the adapter back)
BR/ D = 1, Programming mode:
D return to LOW.
(using level converter).
the level converter).
to LED to connect to V
to LED to connect to V
_SD output is simply an inverted
CC
shutdown
CC
. (VCC = 3.3 V)
CC
. (VCC = 3.3 V)
CC
OHIGH
IHIGH
OLOW
OLOW
OLOW
OLOW
OLOW
HIGH
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2
Document Number 82546
Rev. 1.4, 07-Dec-05
TOIM4232
Vishay Semiconductors
Block diagram of application circuit
Operating the interface circuit at a PC COM - port.
When operating directly with an UART with 3 V - or
5 V - logic, in the application circuit no level converter
is necessary.
VCC = 3.3 V ± 5 %, operating temperature = - 55 °C to + 125 °C
ParameterTest ConditionsSymbolMinTy p.MaxUnit
Input HIGH voltageinputs tolerate levels as high as
5.5 V max. all inputs are Schmitt
trigger inputs
Input LOW voltageV
Input Schmitt trigger hysteresisV
V
CC
IH
IL
hyst
2.73.33.6V
1.72.0V
0.81.1V
0.6V
Document Number 82546
Rev. 1.4, 07-Dec-05
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3
TOIM4232
Vishay Semiconductors
ParameterTest ConditionsSymbolMinTy p.MaxUnit
Input leakage no pull-up/downVIN = VDD or GNDI
Output HIGH voltageI
Output LOW voltageI
Consumption current standbyinputs grounded, no output load
Consumption current dynamicinputs grounded, no output load
= - 2.0 mAV
OH
I
= - 0.5 mAV
OH
= + 2.0 mAV
OL
V
= 3.3 V, T = 25 °C
CC
V
= 3.3 V, T = 25 °C
CC
L
OH
OH
OL
I
SB
I
CC
- 10± 110µA
2.0V
2.4V
0.4V
1µA
2mA
Operation Description
Figure 2 shows a typical example of an RS232 port
interface. The TOIM4232 connects to an RS232 level
converter on one side, and an infrared transceiver on
the other. The internal TOIM4232 baud rate generator
can be software controlled.
When BR/D = 0, the TOIM4232 interprets the channels TD_232 to TD_IR and RD_IR to RD_232 as data
channels.
On the other hand, whenever BR/D = 1, the
TOIM4232 interprets TD_232 as Control Word for
setting the Baud rate. The Baud rate can be programmed to operate from 1200 bit/s to 115.2 kbit/s.
As RS232 level converter, EIA232 or MAX232 or
equivalent are recommended.
When using the TOIM4232 directly connected to an
UART it is compatible to 5 V TTL and 3.3 V CMOS
logic.
Typical external resistors and capacitors are needed
as shown in the TFDx4xxx references.
The output pulse duration can also be programmed,
see chapter "Operation Description". It is strongly recommended using 1.627 µs output pulses to save battery power. As frequency determining component a
Vishay XT49M Crystal is recommended, when no
external clock is available.
We strongly recommend not to use this 3/16 mode
because 3/16 pulse length at lower bit rates consumes more power than the shorter pulse. At a
data rate of 9600 bit/s, the ratio of power consumption of both modes is a factor of 12 (!).
In this case the TOIM4232 interprets the 7 LSBs at
the TD_232 input as a Control Word. The operating
baud rate will change to its supposedly new baud rate
when the BR/D returns back to LOW ("0") Set the
UART to 8 bit, no parity, 1 stop bit.
Control Byte (8 bit)
First CharacterSecond Character
XS2S1S0B3B2B1B0
LSB
X: Do not care
S1, S2: User programmble bit to program the outputs
S1 and S2
S0: Irda pulse select
S0 = (1): 1.627 µs pulses
S0 = (0): 3/16 bit time pulses, not recommended
B0 .. B3: Baud rate select words
Example:
To set TOIM4232 at COM2 port (2F8) to 9600 bit/s
with 3/16 bit time pulse duration send to the
TOIM4232 in programming mode in e.g. "Basic"
OUT &H2F8, (&H6)
For same port, 9600 bit/s and 1.627 µs pulse duration
send
OUT &H2F8, (&H16)
For additionally activating S1 send
OUT &H2F8, (&H36)
Programming the TOIM4232
For correct, data rate dependent timing the
TOIM4232 is using a built-in baud rate generator.
This is used when no external clock is not available as
in RS232 IR-dongle applications. For programming
the BR/D pin has to be set active, BR/D = 1.
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4
Document Number 82546
Rev. 1.4, 07-Dec-05
Baud Rate Select Words
B3B2B1B0
00000 115.2 k
0011 57.6 k
0102 38.4 k
0113 19.2 k
1004 14.4 k
1015 12.8 k
11069.6 k
11177.2 k
100084.8 k
00193.6 k
010A 2.4 k
011B 1.8 k
100C 1.2 k
101D forbidden
110E forbidden
111F forbidden
Note: IrDA standard only supports 2.4, 9.6, 19.2, 57.6, and 115.2 kbit/s.
2nd
Char
Baud Rate
TOIM4232
Vishay Semiconductors
Software for the TOIM4232
UART Programming
For proper operation, the RS232 must be programmed (using 8 bit, 1 stop, no parity) to send a two character control word, YZ. The control
word YZ is composed of two characters, written in hexadecimal, in format: YZ. The transfer rate for programming must be identical with
the formerly programmed data rate, or after resetting the TOIM4232, the default rate of 9600 bit/s is used.
Step.RESETBR/ DTD_UARTRD_UARTRD_IRTD_IRDescription and Comments
1HighXXXXXResets all internal registers. Resets to
2LowXXXXXWait at least 2 ms, to allow start-up of
3LowHighXXXXWait at least 7 µs. TOIM4232 now is set
4LowHighYZ
with Y = 1
for 1.627 µs
Y = 0
3/16 bit
length
5LowLowDATADATADATADATAWith BR/D = 0, TOIM4232 is in the data
*) For programming the UART, refer to e.g., National Semiconductor’s data sheet of PC 16550 UART
XXXSending the Control Word YZ.
IrDA default data rate of 9600 bit/s
internal clock. When external clock is
used: Wait at least 7 µs.
to the Control Word programming mode
Examples: Send "1Z" if 1.627 µs pulses
are intended to be used. Otherwise
send "0Z" for 3/16 bit period pulses.
"Y6" keeps the 9.6 kbit/s data rate.
Z = 0 sets to 115.2 kbit/s, see
programming table.
Wait at least 1 µs for hold-time.
communication mode. Both RESET
and BR/D must be kept LOW ("0")
during data transmission.
Reprogramming to a new data rate can
be resumed by restarting from step 3.
The UART itself also must set to the
correct data rate *).
Document Number 82546
Rev. 1.4, 07-Dec-05
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5
TOIM4232
Vishay Semiconductors
MAX3232CSE
1
J1
CON9
1
6
2
7
3
8
4
9
5
ext.
inputmax
3.3 V DC
+
C3
+
C4
11
10
12
RXD
RTS (BR/D)
TXD
DTR (Reset)
VCC
J2
CON2
C+
3
C1-
4
C2+
5
C2-
T1IN
T2IN
R1OUT
9
R2OUT
1
2
U1
VCC
V+
V-
GND
T1OUT
T2OUT
R1IN
R2IN
+
C1
C2
VCC
R6
Anode
TXD
R4
1
3
5
NC
R3
16
2
6
C6
+
15
14
7
13
8
C7
C5
+
+
R1
Z2
C8
TOIMx232
1
Reset
2
3
4
5
6
7
89
Y1
R2
U2
BR/Data
RD 232
TD 232
Vcc SD
X1
X2
GNDTDLED
C9
Vcc
RD IR
TD IR
S2
S1
NC
RD LED
Application circuit using TFDU4100 with integrated
level shifter MAX3232E. When used directly with
3 V
technical drawings
according to DIN
specifications
0.3
0.2
13011
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10
Document Number 82546
Rev. 1.4, 07-Dec-05
Reel Dimensions
TOIM4232
Vishay Semiconductors
14017
Tape WidthA max.NW1 min.W2 max.W3 min.W3 max.
mmmmmmmmmmmmmm
163305016.422.415.919.4
Document Number 82546
Rev. 1.4, 07-Dec-05
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11
TOIM4232
Vishay Semiconductors
Tape Dimensions in mm
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12
18241
Document Number 82546
Rev. 1.4, 07-Dec-05
TOIM4232
Vishay Semiconductors
Ozone Depleting Substances Policy Statement
It is the policy of Vishay Semiconductor GmbH to
1. Meet all present and future national and international statutory requirements.
2. Regularly and continuously improve the performance of our products, processes, distribution and operating
systems with respect to their impact on the health and safety of our employees and the public, as well as
their impact on the environment.
It is particular concern to control or eliminate releases of those substances into the atmosphere which are
known as ozone depleting substances (ODSs).
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and forbid their use within the next ten years. Various national and international initiatives are pressing for an
earlier ban on these substances.
Vishay Semiconductor GmbH has been able to use its policy of continuous improvements to eliminate the use
of ODSs listed in the following documents.
1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments
respectively
2. Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental
Protection Agency (EPA) in the USA
3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C (transitional substances) respectively.
Vishay Semiconductor GmbH can certify that our semiconductors are not manufactured with ozone depleting
substances and do not contain such substances.
We reserve the right to make changes to improve technical design
and may do so without further notice.
Parameters can vary in different applications. All operating parameters must be validated for each
customer application by the customer. Should the buyer use Vishay Semiconductors products for any
unintended or unauthorized application, the buyer shall indemnify Vishay Semiconductors against all
claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal
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Specifications of the products displayed herein are subject to change without notice. Vishay Intertechnology, Inc.,
or anyone on its behalf, assumes no responsibility or liability for any errors or inaccuracies.
Information contained herein is intended to provide a product description only. No license, express or implied, by
estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay's
terms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any express
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The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications.
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