MDEV-868-PRC datasheet(18/55 Pages) LINX

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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.

HumPRCTM Series Transceiver Status Line Direction Configuration

Line

S0 through S3 are outputs

S0 through S3 are inputs

S4 through S7 are outputs

S4 through S7 are inputs

Figure 23: HumPRCTM 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 HumPRCTM 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

Note: Only one RU should be enabled to transmit an acknowledgement

response for a given IU since multiple acknowledgements will interfere

with each other.

MDEV-868-PRC Datasheet(PDF) 18 Page - Linx Technologies

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