Linx HUM-868-PRC, Руководство по данным

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Configuring the Status Lines
Each of the eight status lines can operate as a digital input or output. The
line direction is determined by bit 0 (ENC01) in the
RCCTL register. By
default, this bit is 1, meaning that the status line directions are determined
by the logic states of the C0 and C1 lines.
When C0 is low, S0 through S3 are outputs; when high, they are inputs.
Likewise, when C1 is low, S4 through S7 are outputs; when high, they
are inputs. This is shown in Figure 23. The C0 and C1 lines are sensed at
power-up and when the
RCCTL register is changed.
When the ENC01 bit is 0 the status line direction is determined by the
RCDIR register. This register acts as a bit map of the status lines. When
bit n is 1, status line Sn is an input line. When bit n is 0, status line Sn is an
output line.
Using the LATCH_EN Line
The LATCH_EN line sets the outputs to either momentary operation or
latched operation. During momentary operation, the outputs go high for as
long as control messages are received instructing the module to take the
lines high. As soon as the control messages stop, the outputs go low.
During latched operation, when a signal is received to make a particular
status line high, it remains high until a separate activation is received to
make it go low. The controlling line on the IU must go low then high to
toggle the latched output on the RU.
Latch operation is controlled by bit 1 in the RCCTL register. When this bit is
a 1 all outputs are latched. When it is a 0, the state of the LATCH_EN line
sets the latching status. In this case, when the LATCH_EN line is high, all of
the outputs are latched.
HumPRC
TM
Series Transceiver 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 23: HumPRC
TM
Series Transceiver Status Line Direction Configuration
Acknowledgement
A responding module is able to send an acknowledgement to the
transmitting module. This allows the initiating module to know that the
responding side received the command.
When the Responding Unit receives a valid REMOTE_ACTIVATE packet,
it immediately checks the state of the ACK_EN line. If it is high the module
sends a REMOTE_CONFIRM packet.
When the Initiating Unit receives a REMOTE_CONFIRM packet, it pulls
the ACK_OUT line high for an amount of time specified by the REMOTE_
CONFIRM packet (20ms by default).
Connecting the ACK_EN line to V
CC
causes the RU to transmit REMOTE_
CONFIRM packets as soon as it receives a valid REMOTE_ACTIVATE
packet. Alternately this line can be controlled by an external circuit that
raises the line when a specific action has taken place. This confirms to the
IU that the action took place rather than just acknowledging receipt of the
signal.
External Amplifier Control
The HumPRC
TM
Series transceiver has two output lines that are designed
to control external amplifiers. The PA_EN line goes high when the module
activates the transmitter. 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 activates the receiver. 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 states of the PA_EN and LNA_EN lines can be read in the LSTATUS
register. This offers a quick way to determine the current state of the radio.
Note: Only one RU should be enabled to transmit an acknowledgement
response for a given IU since multiple acknowledgements will interfere
with each other.