LICAL-TRC-MT001 Linx Technologies, Inc., LICAL-TRC-MT001 Datasheet - Page 6

• Manufacturer Part Number: LICAL-TRC-MT001
• Description: Mt Series Transcoder Data Guide
• Manufacturer: Linx Technologies, Inc.

CREATE MODE
LEARN MODE
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Create Mode allows the generation of a unique address to ensure the
uniqueness of a transmission and prevent unintentional operation of devices.
The MT Series transcoder allows for the creation of 16,777,216 (2
addresses. The assignment of the status lines as inputs or outputs also occurs
in this mode.
Create Mode is entered by pulling the CRT/LRN line high while the ENC_SEL
line is high. The address is randomized for as long as the CRT/LRN line is high
(the ENC_SEL line is not checked again once the process is begun). Once the
line is pulled low, the resulting address is saved in memory and the transcoder
is ready to accept the status line assignments. Each line that is to be an input
should be pulled high. Any lines not taken high are set as outputs. There is no
requirement for the order in which the lines are activated or the time between
activations as long as all of the desired lines are activated within the time out
period. The transcoder saves the assignments and goes to sleep when the
CRT/LRN line is taken high again or when it times out after 15 seconds.
In order for the transcoder to accept transmissions from a specific transcoder, it
must first learn that transcoder’s address. This is done by taking the CRT/LRN
line high then low while the ENC_SEL line is 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 in
the Control Permissions. Each status line on the transmitting side that will be
authorized to control the receiving transcoder needs to be activated. The
receiving transcoder updates the Control Permissions with each valid packet that
contains a new active status line. It is not necessary to hold all of the desired
status lines on the transmitting side high at the same time, simply press each one
that is to be authorized within the time out period. 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
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 overwritten. 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 while the ENC_SEL line is low,
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.
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) possible
TRANSMIT MODE
RECEIVE MODE
TX ID
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
CONFIRM and 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.
When a rising edge is seen on the TR_DATA line, the transcoder enters 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 no valid data is received within 16
or 32mS (dependent on the selected baud rate) then Receive Mode is exited. 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. If Confirmation is enabled, 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.
The transcoder outputs an eight-bit binary number on the SER_IO line to identify
which learned transcoder sent the transmission. The number normally
corresponds to the order in which the transcoder was learned, so the first
transcoder learned will get number ‘1’, the second will get number ‘2’, and so on.
An exception arises when the memory is full, in which case the first numbers are
overwritten as described in the Learn Mode section. An exception also arises if
the serial interface is used to write an address to a specific location in memory.
The TX ID is output with the Status and Custom Data bytes after every valid
packet that is received, as described in the Serial Output section.
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