LICAL-TRC-MT Linx Technologies Inc, LICAL-TRC-MT Datasheet - Page 5

• Manufacturer Part Number: LICAL-TRC-MT
• Description: IC TRANSCODER MT BI-DIR 20-SSOP
• Manufacturer: Linx Technologies Inc
• Series: MTr
• Type: Transcoderr

Specifications of LICAL-TRC-MT

• Package / Case: 20-SSOP
• Applications: RF, IR
• Mounting Type: Surface Mount
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: LICAL-TRC-MTTR

LEARN MODE
RECEIVE MODE
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In order for the transcoder to accept transmissions from another transcoder, it
must first learn the other transcoder’s address. This is done by taking the
CRT/LRN line high then low to place the transcoder into Learn Mode. Once in
Learn Mode, the MODE_IND line starts switching, allowing for connection of a
LED to provide visual indication that the transcoder is ready to accept a new
address. This continues until the CRT/LRN line goes high again or until a time-
out after 15 seconds.
The transcoder looks for a valid transmission from another transcoder and
records the received address. It also records the status line that was activated
as the Control Permissions. Each status line that will be authorized to control the
transcoder is activated, and the Control Permissions are updated with each valid
packet. When the CRT/LRN line is taken high again or the transcoder times-out
after 15 seconds, the recorded address and Control Permissions are saved in
memory and the transcoder exits Learn Mode, and returns to sleep.
The MT Series transcoder can store up to sixty unique addresses in its memory.
If a transcoder is re-learned, its permissions are updated. The transcoder does
not create a second instance of the same address. If a new transcoder is learned
while the memory is full, then the transcoder writes the new address over the first
address in memory. It flashes the MODE_IND line five times to indicate that the
memory is full and the next address learned will overwrite the first. All of the
learned addresses are retained if power is removed from the transcoder.
If the CRT/LRN line is held high for ten seconds, then the transcoder erases all
of the stored addresses from memory. The MODE_IND line goes high for as long
as the CRT/LRN line is high, but after the ten seconds it goes low. Once the
CRT/LRN line is pulled low again, the MODE_IND line goes high for two seconds
to indicate that the memory has been cleared.
When a rising edge is seen on the TR_DATA line, the transcoder enters Receive
Mode. It begins by pulling the TR_PDN line high to activate the transceiver and
pulling the TR_SEL line low to place the transceiver into receive mode. It then
looks for a valid packet, meaning that there are no errors and that the received
address matches one that is saved in memory. In addition, if Targeted Device
Addressing is enabled, then the received targeted address must match the
transcoder’s local address. If there is a match, then the transcoder pulls the
MODE_IND line high as an indication that a valid signal was received. It
compares the received commands to the Control Permissions associated with
the transcoder that sent the signal, and reproduces the states of the authorized
status lines on the originating transcoder on its own status lines. The transcoder
then pulls the TR_SEL line high to place the transceiver into transmit mode and
sends a confirmation to the originating transcoder. It also outputs the ID of the
originating transcoder, a Command Byte that represents the states of the status
lines, and a custom data byte programmed by the user. It then looks for the next
valid data packet. If, at any time, an error or an unknown address is detected,
then the transcoder ignores the packet and looks for the next one. If the 131mS
timer runs out before any valid packets are received, then the transcoder goes
back to sleep.
TRANSMIT MODE
LATCH MODE
TARGETED DEVICE ADDRESSING
When any of the status lines that are set as inputs go high, the transcoder enters
Transmit Mode. It pulls the TR_PDN line high to activate the transceiver, pulls
the TR_SEL line high to place the transceiver into transmit mode, records the
states of the status lines, assembles the packet, and sends it through the
TR_DATA line. The transcoder then pulls the TR_SEL line low to place the
transceiver into receive mode and looks for a confirmation from the remote
transcoder. If a valid confirmation is received, then the transcoder pulls the
CONFIRM line high, otherwise it checks to see if any status line inputs are high.
The transcoder continues this for as long as any of the status line inputs are high,
updating the states of the status lines with each transmission. Once all of the
input lines are pulled low, the transcoder finishes the current transmission, pulls
TR_PDN low to deactivate the transceiver, and goes to sleep.
The MT has the ability to control the status line byte through the SIE. An external
microcontroller or PC can be used to write the desired input states and a packet
counter into the transcoder. The transcoder uses this byte instead of looking at
the status line inputs, sends the specified number of packets, then goes to sleep.
This is subject to the I/O settings, so lines set as outputs cannot be set high.
The transcoder has two output options based on the state of the LATCH line. If
the line is low, then all of the status line outputs will be momentary, meaning that
they will only be high for as long as a valid signal is received. Once the signal
stops and the transcoder times out, the lines are pulled low.
If the LATCH line is high, then the transcoder will use a Latch Mask on the
outputs. By default, all of the status line outputs are set to latch, so the
transcoder will pull a data line high upon reception of a valid signal and hold it
high until the signal is received a second time, at which point the transcoder will
pull it low. The transcoder must see a break and time out between valid
transmissions before it will toggle the outputs.
The Latch Mask can be changed through the SIE so that individual status lines
can be set as latched or momentary. The Serial Mode section has more
information on the SIE.
One of the powerful features of the MT is Targeted Device Addressing. This is
the ability to target the specific device that is to acknowledge the transmission.
This is accomplished by entering the address of the target device through the
SIE. For example, if a master controller needs to have Device 10 activate, a
microcontroller or PC can be used to program the address of Device 10 into the
transcoder in the master controller. The transcoder will then broadcast that
address with the commands, and only Device 10 will respond. This enables
many types of master-slave, peer-to-peer, and even basic networking systems
to be quickly realized. The simple command set and open architecture allow
such systems to be implemented in many ways. Application Note AN-00157
goes into this feature in more detail.
Targeted Device Addressing only needs to be enabled on the transmitting side.
The receiving side identifies the packet as a targeted packet and responds
appropriately. This option is disabled by default.
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