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LATCH Mode
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 of
Receive Mode 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.
Targeted Device Addressing
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 Device 10
to 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.