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packet_format [2014/08/22 17:39]
jcoxon
packet_format [2020/06/27 23:02] (current)
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: 2020/06/27 23:02 (external edit)