mirrors/embedded-trainings-2020
1
0
Fork 0
mirror of https://github.com/ferrous-systems/embedded-trainings-2020.git synced 2025-02-10 06:32:21 +00:00
Code Issues Projects Releases Wiki Activity

Update embedded-workshop-book/src/beginner-next-steps.md

Browse source 
Co-authored-by: Lotte Steenbrink <lotte@zombietetris.de>
This commit is contained in:
Jorge Aparicio 2020-07-14 10:01:33 +00:00 committed by GitHub
parent a7051bd4e3
commit 554a75595e
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
embedded-workshop-book/src/beginner-next-steps.md
View file

@ -6,7 +6,7 @@ If you've already completed the main workshop tasks or would like to explore mor
If you check the API documentation of the `Radio` abstraction we have been using you'll notice that we haven't used these methods: `energy_detection_scan()`, `set_cca()` and `try_send()`.
The first method scans the currently selected channel (see `set_channel`), measures the energy level of ongoing radio communication in this channel and returns the maximum energy observed over a span of time. This method can be used to determine what the *idle* energy level of a channel is. If there's non-802.15.4 traffic ongoing on this channel the method will return a high value.
The first method scans the currently selected channel (see `set_channe()l`), measures the energy level of ongoing radio communication in this channel and returns the maximum energy observed over a span of time. This method can be used to determine what the *idle* energy level of a channel is. If there's non-IEEE 802.15.4 traffic on this channel the method will return a high value.
Under the 802.15.4 specification, before sending a data packet devices must first check if there's communication going on in the channel. This process is known as Clear Channel Assessment (CCA). The `send` method we have been used performs CCA in a loop and sends the packet only when the channel appears to be idle. The `try_send` method performs CCA *once* and returns the `Err` variant is the channel appears to be busy. In this failure scenario the device does not send any packet.