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Merge pull request #94 from gdetrez/patch-1

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Fix typos in beginner-next-steps.md
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James Munns 2020-08-04 23:42:48 +02:00 committed by GitHub
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embedded-workshop-book/src/beginner-next-steps.md
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@ -6,9 +6,9 @@ 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_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.
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-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.
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 if the channel appears to be busy. In this failure scenario the device does not send any packet.
The `Radio` abstraction supports 2 CCA modes: `CarrierSense` and `EnergyDetection`. `CarrierSense` is the default CCA mode and what we have been using in this workshop. `CarrierSense` will only look for ongoing 802.15.4 traffic in the channel but ignore other traffic like 2.4 GHz WiFi and Bluetooth. The `EnergyDetection` method is able to detect ongoing non-802.15.4 traffic.