Linx Technologies HUM-xxx-RC - Manual (Page 15)

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Configuring the Status Lines
Each of the eight status lines can operate as a digital input or output.
Configuring their direction can be done in two ways. Basic operation uses
the C0 and C1 lines. When C0 is low, S0 through S3 are outputs; when C0
is high, S0 through S3 are inputs. Likewise when C1 is low, S4 through S7
are outputs; when C1 is high, S4 through S7 are inputs. This is shown in
Figure 29.
Advanced operation uses the CDI to set each line direction individually with
the Status Line I/O Mask item. In addition, the Control Source Item is used
to tell the module to use the serial command instead of the hardware line
configuration.
Up to two of the status lines in the S4 through S7 group can be configured
as analog inputs. An analog input line is used only for reading an input line
voltage and converting it to a digital value (Analog to Digital Conversion,
ADC). The analog input selection is primary, overriding digital input/output
selection. An analog input reading can be transmitted to another module
when functioning as either an IU or RU. The digitized reading must be
read through a serial command at the receiving end. The analog setting is
configured through the CDI using the Analog Input Select item.
Please see Reference Guide RG-00104: the HumRC TM Series Command
Data Interface for details on the CDI.
External Amplifier Control
The HumRC TM Series transceiver has two output lines that are designed
to control external amplifiers. The PA_EN line goes high when the module
enters transmit mode. This can be used to activate an external power
amplifier to boost the signal strength of the transmitter. The LNA_EN line
goes high when the module enters receive mode. This can be used to
activate an external low noise amplifier to boost the receiver sensitivity.
These external amplifiers can significantly increase the range of the system
at the expense of higher current consumption and system cost.
The Pair Process
The Pair process enables two transceivers to communicate with each
other. Each transceiver has a local 32-bit address that is transmitted with
every packet. If the address in the received packet is not in the RU’s Paired
Module List, then the transceiver does not respond. Adding devices to
the authorized list is accomplished through the Pair process or by a serial
command. Each module can be paired with up to 40 other modules.
The Pair process is initiated by taking the PAIR line high or by sending the
Pair Control serial command on both units to be associated. Activation
on the PAIR line can either be a momentary pulse (less than two seconds)
or a sustained high input, which can be used to extend the search and
successful pairing display. With a momentary activation, the search is
terminated after 30 seconds. If Pairing is initiated with a sustained high
input, the search continues as long as the PAIR input is high.
When Pair is activated, the module displays the Pair Search sequence
on the MODE_IND line (Figure 30) and goes into a search mode where it
looks for another module that is also in search mode. It alternates between
transmit and receive, enabling one unit to find the other and respond.
Once bidirectional communication is established, the two units store each
other’s addresses in their Paired Module List with full Permissions Mask
and display the Pair Found sequence on their MODE_IND lines. The Pair
Found sequence is displayed for at least 3 seconds. If PAIR is held high,
the Pair Found display is shown for as long as PAIR is high. If a paired
unit is already in the Paired Module List, then no additional entry is added
though the existing entry’s Permissions Mask may be modified.
When Pairing is initiated, the module pairs with the first unit it finds that is
also in Pair Search. If multiple systems are being Paired in the same area,
such as in a production environment, then steps should be taken to ensure
that the correct units are paired with each other.
The Pair process can be cancelled by taking PAIR high a second time or by
issuing the Pair Control command with Cancel Pairing option.
If the address table is full when the PAIR line is raised, the Pair Table Full
sequence is displayed on the MODE_IND line for 10 seconds and neither of
the Pairing units stores an address. In this case, the module should either
be reset to clear the address table or the serial interface can be used to
remove addresses.
Status Line Direction Configuration
Line 0 1
C0 S0 through S3 are outputs S0 through S3 are inputs
C1 S4 through S7 are outputs S4 through S7 are inputs
Figure 29: MODE_IND Timing