Smartrek Technologies 900 MHz Mesh Network Long Range Transceiver Module : Integration Guide : Page 9

SMK900 Integration Guide Revision 4

The primary means for network segregation is of course the selection of the FHSS channel via a

configuration variable named HOPTABLEID. The current implementation allows for values between 0

and 5 (i.e. 6 different hop tables).

Transparent and Protocol-formatted Mode

A SMK900 based network can be configured to use either the transparent or the protocol-formatted mode

for the serial port interface.

Transparent

The transparent mode allows for basic, unsynchronized integration which emulate a simple

point-to-multipoint serial link between a gateway and its nodes. In this case, the message is assumed

to be of standard ASCII format, with the special ASCII terminator characters 0x13 (Carry) or 0x10

(Line Feed) are used as markers to trigger the end of a message stream, and thus to trigger

transmission over radio waves.

Protocol-formatted

Protocol-formatted messages also referred to as Application Programing Interface (API) are

discussed in the following sections. rotocol-formatted messages usea start-of-message marker,

followed by message length, message information type (or command byte), an optional string of

MAC addresses, and finally, the payload.

Virtual machine

Description

SMK900 radios feature an embedded Virtual Machine (VM) allowing Over-The-Air (OTA) firmware

updates. This allows application-specific user scripting to control the internal modules of the SMK900

radio and ease interfacing with external devices. The main processor controls and manages wireless

mesh operations and executes VM user scripts.

TheVirtual Machine is available when the serial protocol is configured to protocol-formatted mode

(not to transparent mode). An IDE is available for Virtual Machine development, which includes basic

compiler, disassembler, node configuration and VM upload/erase functions as well as direct node serial

connection and OTA firmware node upload with a gateway.

Virtual Machine Triggers

Virtual Machine script execution is managed by the mesh network process. This is to ensure mesh

operation priority over the Virtual Machine. VM execution is triggered by various events, which are

defined in the table below.

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