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12
If the LEARN line is held high for ten seconds, then the decoder will erase
all of the stored Code Words from memory. The MODE_IND line will be high
for as long as the LEARN line is high, but after the ten seconds it will go
low. Once the LEARN line is pulled low again, the MODE_IND line will go
high for two seconds to indicate that the memory has been cleared.
LATCH Mode
The MS Series decoder has two output options based on the state of the
LATCH line. If it is low, then the data lines 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 decoder times out, the lines are pulled low.
If the LATCH line is high, the decoder 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 decoder will pull it low. The decoder must
see a break and time out between valid transmissions before it will toggle
the outputs. The minimum required time-out periods are listed in the
Receive Mode section.
Receiver Control Mode
If the RX_CNTL line is pulled high when the decoder initially powers on,
then the decoder will enter Receiver Control Mode. Once in this mode,
the RX_CNTL line becomes an output that can be attached to the PDN or
V
CC line of a Linx receiver or a similar input on another receiver. This allows
the decoder to power down the receiver when it is not required, thereby
reducing current consumption and prolonging battery life. The decoder
draws full current in this mode, but an active receiver will typically draw
much more than the decoder, so a savings is realized.
The decoder will activate the receiver for approximately one packet’s time
plus 10mS for the receiver to power up, so the actual “on” time depends
on the baud rate chosen by the user. This time can be calculated in
milliseconds as (60/Baud Rate)(1000) + 10. The “off” time is nine times
the “on” time, resulting in a 10% duty cycle, greatly reducing the receiver’s
current consumption. However, there may be a lag time from when the
encoder activates to when the decoder responds. The decoder will enter
Receive Mode when it sees a valid packet, so there would only be a lag for
the first packet. This can be reduced by selecting a higher baud rate.
If this feature is not going to be used, then this pin should be tied to
ground. If it is tied to V
CC, then the decoder will create a short when it pulls