SN260 datasheet(34/88 Pages) STMICROELECTRONICS

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EmberZNet serial protocol

SN260

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EmberZNet serial protocol

EmberZnet Serial Protocol (EZSP)has been designed to be very familiarr to customers who

have used the EmberZNet 2.x stack API. The majority of the commands and responses are

functionally identical to those found in EmberZNet 2.x. The variations are due mainly to the

timing differences of running the application on a separate processor across a serial

interface. Communication between the SN260 and the Host consists of a two-message

transaction. The Host sends a command message to the SN260 and then the SN260 sends

a response message to the Host. If the SN260 needs to communicate asynchronously with

the Host, it will indicate this by using the interrupt line and then waiting for the Host to send

the callback command.

All EZSP frames begin with a Frame Control Byte followed by a Frame ID Byte. The format

of the rest of the frame depends on the frame ID. Section 7.3: Protocol format on page 38

defines the format for all the frame IDs. Most of the frames have a fixed length. A few, such

as those containing application messages, are of variable length. The frame control

indicates the direction of the message (command or response). For commands, the frame

control also contains power management information, and for responses it also contains

status information.

When a command contains an application message, the Host must supply a one-byte tag.

This tag is used in future commands and responses to refer to the message. For example,

when sending a message, the Host provides both the message contents and a tag. The tag

is then used to report the fate of the message in a later response from the SN260.

7.1

Byte order

All multiple octet fields are transmitted and received with the least significant octet first, also

referred to as little endian. This is the same byte order convention specified by 802.15.4 and

ZigBee. Note that EUI64 fields are treated as a 64-bit number and are therefore transmitted

and received in little endian order. Each individual octet is transmitted with the most

significant bit first, as shown in Section 6.1: Physical interface configuration on page 22.

7.2

Conceptual overview

This section provides an overview of the concepts that are specific to the SN260 or that

differ from the EmberZNet 2.x stack API. The commands and responses mentioned in this

overview are described in more detail later in this document.

7.2.1

Stack configuration

The Host can use the version command to obtain information about the firmware running

on the SN260. There are a number of configuration values that affect the behavior of the

stack. The Host can read these values at any time using the getConfigurationValue

command. After the SN260 has reset, the Host can modify any of the default values using

the setConfigurationValue command. The Host must then provide information about

the application endpoints using the addEndpoint command.

Table 17 gives the minimum, default and maximum values for each of the configuration

values. Also listed is the RAM cost. This is the number of bytes of additional RAM required

to increase the configuration value by one. Since the total amount of RAM is fixed, the

SN260 Datasheet(PDF) 34 Page - STMicroelectronics

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