Zigbee Protocol
The two major frames we care about are transmit/receive frames and response frames.
Example Transmit Frame:
7E | 00 19 | 10 | 01 | 00 13 A2 00 41 B1 6D 1C | FF FE | 00 | 00 | 53 45 4E 54 20 46 52 4F 4D 20 42 | D1
Breakdown of the message:
Start Deliminator: signifies that the message is starting, always use 7E
1 byte
7E
Length of message: the number of bytes between length and checksum, not including length and checksum
2 bytes
00 19
Frame type: should be 10 for transmit, 90 for receive, and 8B for transmit response (but responses will be covered after transmit frames)
1 byte
10
Frame ID: lets you order messages, and associate transmit frames with their appropriate responses. (optional as far as I know, I was able to send out frames with the same IDs one after another
1 byte
01
64 Bit address: for transmit frames, it is the destination, for receive frames its the source
8 bytes
00 13 A2 00 41 B1 6D 1C
16 bit address: use FF FE for this. As far as we can figure that is the default value for when you dont have a 16 bit address, which we don’t.
2 bytes
FF FE
Broadcast radius: represents the number of hops in a mesh network the message should make before giving up if it cant reach the target. leave it at 00, which means no limit (best guess on this)
1 byte
00
Options: leave at 00.
1 byte
00
Message: this will contain the data that is actually being sent
variable bytes
53 45 4E 54 20 46 52 4F 4D 20 42
Checksum: the sum of the bytes between length and checksum, not including length and checksum
1 byte
D1
Example response Frame:
7E | 00 07 | 8B | 01 | FF FE | 00 | 00 | 00 | 76
Breakdown of the message:
Start Deliminator: signifies that the message is starting, always use 7E
1 byte
7E
Length of message: the number of bytes between length and checksum, not including length and checksum
2 bytes
00 19
Frame type: should be 10 for transmit, 90 for receive, and 8B for transmit response (but responses will be covered after transmit frames)
1 byte
10
Frame ID: lets you order messages, and associate transmit frames with their appropriate responses. (optional as far as I know, I was able to send out frames with the same IDs one after another
1 byte
01
16 bit address: use FF FE for this. As far as we can figure that is the default value for when you dont have a 16 bit address, which we don’t.
2 bytes
FF FE
TX retry count: the number of times the message was resent
1 byte
00
Delivery Status: 00 for success, anything else is failure
1 byte
00
Discovery status: 00 for success, 25 means root not found, which as far as I can figure, means that the destination wasnt found
1 byte
00
Checksum: the sum of the bytes between length and checksum, not including length and checksum
1 byte
76
How do the two frame types work together?
To receive a message, it’s simple. You receive a receive frame (which has the same basic structure as a transmit frame) that you can decode and use.
To send a message, you must first construct a transmit frame, send it to the Xbee. Then listen for transmit response to ensure that the packet was sent properly.
What has been done to get the Xbees working?
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