Linx Technologies LICAL-TRC-MT - Manual (Page 8)

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Create Mode
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
24 ) possible addresses. The assignment of the status lines as inputs or
outputs also occurs in this mode.
Create Mode is entered by holding the ENC_SEL line high and pulling the
CRT/LRN line 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.
Learn Mode
In order for the MT 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 to place the transcoder into Learn Mode. Once in
Learn Mode, the MODE_IND line starts switching, allowing for connection
of an 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 is 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, 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.
Transmit Mode
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.