User Manual
PRO-FLEX SERIES TRANSCEIVER MODULES
HOST PROTOCOL GUIDE
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PFLX-UG-0001-00-09 Copyright © 2009 LS Research, LLC Page 5 of 37
2 Host Protocol
This document describes in detail the message protocol used to communicate
between a Host Device and a Pro-FLEX RF Module microprocessor.
2.1 Host Serial Protocol Overview
Header Payload Trailer
Field
Start
Byte
Length Type Data
Checksum
End Byte
# Bytes
1 1 1 n 1 1
Figure 1 Host Protocol Message Format
Field Name Field Description
Start Byte The start byte is the first byte in a packet (0x01).
Length The total length of the entire packet in bytes (5 + n).
Type The packet type byte indentifies the intent of the packet.
Local/Remote
Designates whether the packet is intended for the local “hardwired” module
(0x00) or the remote module (0x01). If targeting a remote module, then the local
hardwired module forwards the message over the RF to the remote module. The
remote module’s address is defined in the “Remote Address” field below.
Remote
Address
Two byte address (LSB to MSB) of the remote module the message is intended
for. In order for this address to be valid the “Local/Remote” field, described
above, must be set to 0x01. When the “Local/Remote” field is 0x00 then this field
is ignored.
Data
n bytes of data which pertains to the type of the packet. The data is variable
depending on the type of packet. For some packets there is no data.
Checksum
The checksum is the least significant byte of the result of summing bytes from the
Start through the Payload.
End Byte The end byte is the last byte in a packet (0x04).
Table 2 Host Serial Protocol Field Descriptions
2.2 Example Host Protocol Message Exchange
Below is an example that shows what a complete host serial packet would look
like for a “Query PAN ID” and a “Respond with PAN ID” message exchange.
This example assumes the PAN ID is being queried from the local “hardwired”
module.
Host -> Module – (Query PAN ID – Type 0x02)
< 0x01 0x08 0x02 0x00 0x00 0x00 0x0B 0x04 >