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packet_format [2014/08/22 17:39]
jcoxon
packet_format [2016/08/31 16:30] (current)
russ
Line 1: Line 1:
-====== Guide to Packet Format ====== +[[https://github.com/UKHASnet/​protocol/​blob/​master/​protocol.md|This page has moved to github.]]
- +
-Example packet: +
-<​code>​2iL51.498,​-0.0527T21R0[AB,​AA]<​/code> +
- +
-  - **Repeat Number**: The first byte contains the number of repeats - most commonly this is set to 3 however if you want the packet to go further then you can increase this numberEverytime a packet is repeated the node subtracts 1 from this number, once it reaches 0 the packet will not be repeated. +
-  - **Sequence Count**: this cycles from '​b'​ to '​z'​ allowing packets to be distinguished,​ '​a'​ is only transmitted on boot of the node. +
-  - **Data**: this is where the main packet data is placed, for example location or temperature. Each data type starts with an identifying character and then each value separated by a comma. E.g. <​code>​T18.5,​23,​10</​code>​ For more information see [[packet_data_types|Packet Data Types]]. The data section is variable in length but ideally the shorter the packet the better. +
-  - **Path**: enclosed within '​['​ and '​]'​ each node adds its node ID separated by a comma at the end. Each node ID can be up to a maximum of 16 bytesNodes only repeat packets that they haven'​t repeated before (to avoid loops) so before repeating the node needs to check for its node ID in the path section. For example (pseudocode) <​code>​ +
-1) detect final in string/​array +
-2) replace ​with ,your_ID] (comma followed by your_ID followed by square end bracket) +
-</​code>​+
packet_format.txt · Last modified: 2016/08/31 16:30 by russ