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9
are generally either recognized or denied based on the address. If the
addresses match, the state of all data lines will be recognized and output.
The MT Series allows a user or manufacturer to establish a user identity
and profile that determines which inputs will be acknowledged. Let’s apply
this capability practically to our example: a three door garage houses
Dad’s Corvette, Mom’s Mercedes, and Son’s Yugo. With most competitive
products, any user’s keyfob could open any garage door as long as the
addresses match. In a Linx MT-based system, each individual keyfob could
easily be configured to open only certain doors (guess which one Son gets
to open!)
As you review this data guide keep in mind that it seeks to cover the full
scope of the MT’s capabilities. The implementation for a simple one button
remote will be different than a powerful targeted control, command, or
status network. While it is unlikely that all of the features of this part will be
utilized at any one time, their availability provides great design flexibility and
opens up many new opportunities for product innovation.
Transceiver Power Control
The transcoder has the option to control power to an external transceiver
through the TR_PDN line. This line can be connected to a power down or
supply line of a Linx transceiver or a similar input on another transceiver.
This allows the transcoder to power down the transceiver when it is not
required, thereby reducing current consumption and prolonging battery life.
The transcoder pulls the TR_SEL line low to place the transceiver into
receive mode and looks for valid data for 16mS or 32mS, depending on
the baud rate. If data is present on the TR_DATA line, then the transcoder
enters Receive Mode. If no data is present, then the transcoder pulls the
TR_PDN line low to power down the transceiver and goes to sleep for
150mS or 295mS. The “off” time is approximately nine times the “on” time,
resulting in a 10% duty cycle, greatly reducing the transceiver’s current
consumption. However, there may be a lag time from when the transmitting
transcoder activates to when the receiving transcoder responds. The
transcoder enters Receive Mode when it sees a valid packet, so there
would only be a lag for the first packet.
This cycle continues until data is received placing the transcoder into
Receive Mode, until a status input line is taken high placing it into Transmit
Mode, or the CRT/LRN line is taken high placing it into Serial, Learn, or
Create Modes. If a faster response time is desired, then the TR_PDN line
can be left disconnected.