MDEV-868-PRC datasheet(17/55 Pages) LINX

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Operation with the HumPROTM Series

The commands from the HumPRCTM Series module can be received by

a HumPROTM Series transceiver and vice versa. The modules should be

joined using the normal Join Process. The IU sends a REMOTE_ACTIVATE

packet and accepts a REMOTE_CONFIRM reply.

A microcontroller connected to the HumPROTM Series can be programmed

to take action based on the STATUS byte in a REMOTE_ACTIVATE packet

that is received from a HumPRCTM Series module. It can also read out the

packet header and know the address of the sending module and respond

with a REMOTE_CONFIRM packet to activate the ACK_OUT line on the

HumPRCTM module.

Likewise, the microcontroller can be programmed to send a REMOTE_

ACTIVATE packet to a HumPRCTM Series module. This opens up many

options for creative mixed-mode design.

Remote Activation

The REMOTE_ACTIVATE packet consists of six bytes:

0x03 0x00 0x00 0x00 0x10 <STATUS>

The first byte is 0x03 with the next three bytes 0x00. Byte five is 0x10

which indicates a Remote Activation. Byte six is the STATUS byte, which is

a bit map of the button states. Bit 0 corresponds to button S0 and so forth.

Each bit is 1 if the corresponding line is high.

Remote Confirm

The REMOTE_CONFIRM packet has the following format:

0x03 0x00 0x00 0x00 0x11 <DURATION> <ALIVE>

The first two bytes are 0x00 0x11 and indicate that the packet is a remote

confirm packet.

The DURATION byte indicates the amount of time that the ACK_OUT line

should be held high. This value is multiplied by 10ms. If the value is 0, the

output is immediately taken low. The default value is 0x02 for 20ms. This

value overrides the effect of a previously received REMOTE_CONFIRM

packet.

The ALIVE byte indicates how long after the transmission the IU module

should stay awake in receive mode. This value is multiplied by 0.1s. Once

this duration expires, the module returns to sleep mode.

This message is transmitted to the IU’s address. It must be received by the

IU within one second of initial transmission or within the ALIVE interval of

the previous REMOTE_CONFIRM packet.

Carrier Sense Multiple Access (CSMA)

CSMA is an optional feature. It is a best-effort delivery system that listens

to the channel before transmitting a message. If CSMA is enabled and

the module detects another transmitter on the same channel, it waits until

the active transmitter finishes before sending its payload. This helps to

eliminate RF message corruption and make channel use more efficient.

When a module has data ready to transmit and CSMA is enabled, it listens

on the intended transmit channel for activity. If no signal is detected,

transmission is started.

If a carrier is detected with an RSSI above the CSMA threshold in the

CSRSSI register, transmission is inhibited. If a signal below the threshold is

detected that has a compatible preamble or packet structure, transmission

is also inhibited.

If the module is synchronized from a recent packet transfer, it waits for a

random interval, then checks again for activity. If the detected carrier lasts

longer than the time allowed for the current channel, the module hops to

the next channel in the hop sequence and again waits for a clear channel

before transmitting.

If the module is not synchronized, it hops to the next channel and again

checks for interference. When no activity is detected it starts transmitting.

This feature is enabled by default so that the module will comply with ETSI

requirements. Disabling it could impact compliance to the regulations and

require an external means of controlling transmitter on time and duty cycle.

MDEV-868-PRC Datasheet(PDF) 17 Page - Linx Technologies

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