Class XBeePacketParser

This class reads and parses XBee packets from the input stream returning an XBeePacket which can be casted later to the corresponding high level specific API packet.

Inheritance

System.Object

XBeePacketParser

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: XBeeLibrary.Core.Packet

Assembly: XBeeLibrary.Core.dll

Syntax

public class XBeePacketParser

Remarks

All the API and API2 logic is already included so all packet reads are independent of the XBee operating mode.

Two API modes are supported and both can be enabled using the AP (API Enable) command:

• API1 - API Without EscapesThe data frame structure is defined as follows: Start Delimiter Length Frame Data Checksum (Byte 1) (Bytes 2-3) (Bytes 4-n) (Byte n + 1) +----------------+ +-------------------+ +--------------------------- + +----------------+ | 0x7E | | MSB | LSB | | API-specific Structure | | 1 Byte | +----------------+ +-------------------+ +----------------------------+ +----------------+ MSB = Most Significant Byte, LSB = Least Significant Byte
• API2 - API With Escapes The data frame structure is defined as follows: Start Delimiter Length Frame Data Checksum (Byte 1) (Bytes 2-3) (Bytes 4-n) (Byte n + 1) +----------------+ +-------------------+ +--------------------------- + +----------------+ | 0x7E | | MSB | LSB | | API-specific Structure | | 1 Byte | +----------------+ +-------------------+ +----------------------------+ +----------------+ \____________________________________________________________________/ \/ Characters Escaped If Needed MSB = Most Significant Byte, LSB = Least Significant Byte

  When sending or receiving an API2 frame, specific data values must be escaped (flagged) so they do not interfere with the data frame sequencing.

  To escape an interfering data byte, the byte 0x7D is inserted before the byte to be escaped XOR'd with 0x20.

  The data bytes that need to be escaped:

  • 0x7E - Frame Delimiter (HEADER_BYTE)
  • 0x7D - Escape (ESCAPE_BYTE)
  • 0x11 - XON (XON_BYTE)
  • 0x13 - XOFF (XOFF_BYTE)

The Length field has a two-byte value that specifies the number of bytes that will be contained in the frame data field. It does not include the checksum field.

The frame data forms an API-specific structure as follows: Start Delimiter Length Frame Data Checksum (Byte 1) (Bytes 2-3) (Bytes 4-n) (Byte n + 1) +----------------+ +-------------------+ +---------------------------+ +----------------+ | 0x7E | | MSB | LSB | | API - specific Structure | | 1 Byte | +----------------+ +-------------------+ +---------------------------+ +----------------+ /
/ API Identifier Identifier specific data
+------------------+ +------------------------------+ | cmdID | | cmdData | +------------------+ +------------------------------+

The cmdID frame (API-identifier) indicates which API messages will be contained in the cmdData frame (Identifier-specific data).

To test data integrity, a checksum is calculated and verified on non-escaped data.

Methods

ParsePacket(Byte[], OperatingMode)

Parses the bytes from the given array depending on the provided operating mode and returns the API packet.

Declaration

public XBeePacket ParsePacket(byte[] packetByteArray, OperatingMode mode)

Parameters

Type	Name	Description
System.Byte[]	packetByteArray	Byte array with the complete frame, starting from the header and ending in the checksum.
OperatingMode	mode	XBee device operating mode.

Returns

Type	Description
XBeePacket	Parsed packet from the given byte array.

Remarks

The operating mode must be API or API_ESCAPE

Exceptions

Type	Condition
InvalidPacketException	If there is not enough data in the array or if there is an error verifying the checksum or if the payload is invalid for the specified frame type.
System.ArgumentException	If mode != API and if mode != API_ESCAPE
System.ArgumentNullException	If packetByteArray == null.

See Also

XBeePacket

API

API_ESCAPE

ParsePacket(Stream, OperatingMode)

Parses the bytes from the given inputStream depending on the provided mode and returns the API packet.

Declaration

public XBeePacket ParsePacket(Stream inputStream, OperatingMode mode)

Parameters

Type	Name	Description
System.IO.Stream	inputStream	Input stream to read bytes from.
OperatingMode	mode	XBee device operating mode.

Returns

Type	Description
XBeePacket	Parsed packet from the input stream.

Remarks

The operating mode must be API or API_ESCAPE.

Exceptions

Type	Condition
System.ArgumentException	If mode is invalid or if the inputStream cannot be read.
System.ArgumentNullException	If inputStream is null.
InvalidPacketException	If there is not enough data in the stream or if there is an error verifying the checksum or if the payload is invalid for the specified frame type.

See Also

APIFrameType

XBeePacket

OperatingMode