chester: common-functionality: Document manual reset procedure (#115)

Signed-off-by: Marek Maškarinec <[email protected]>

chester/catalog-applications/common-functionality.md

@@ -28,7 +28,7 @@ Then apply changes by typing `config save`. The device will reboot and use the c
 
 ## Button Behaviour
 
-Applications define actions for the mainboard button. The actions are chosen based on the number of consecutive presses of the button. Before an action is executed, **CHESTER** will blink the orange LED *N* times, indicating the amount of consecutive presses. The actions are:
+Applications define actions for the mainboard button. The actions are chosen based on the number of consecutive presses of the button. Before an action is executed, **CHESTER** will blink the orange LED once for each button press, indicating the amount of consecutive presses. The actions are:
 
 | Number of presses | Action                                      |
 | :---------------: | :------------------------------------------ |
@@ -64,9 +64,27 @@ config save
 
 This will apply the changes and restart the application. After the restart, you can verify the settings changed using the `app config show` command.
 
+If you want to reset the configuration back to the default state, you can do so using `config reset`. In rare cases, when the CHESTER console isn't available, you can use the manual reset procedure. To initiate this, holding down the button while CHESTER boots. After holding the button for around 5 seconds, CHESTER will start rapidly blinking. At this point, you can release the button to proceed with the reset. If you continue holding the button until CHESTER stops blinking, the reset will be aborted.
+
+:::caution
+
+Reseting the configuration will also reset the connection parameters for LTE and LoRaWAN, which can result in CHESTER unable to communicate.
+
+:::
+
 You might also change configuration remotely over HARDWARIO Cloud using [**Config downlink command**](../../cloud/cloud-v2/downlink#config).
 In cloud you don't send the `config save` command.
 
+## Report Interval Jitter
+
+The periodic sending of data with `interval-report` has intentional jitter. This is used in case lot of CHESTERs are placed near each other, so they don't transmit at the same time if they have set the same interval. This jitter is random in the range of ±20 % of `interval-report`.
+
+For example, if `interval-report` is set to 100 seconds, you can receive periodic data where two messages have a time difference from 80 (-20%) to 120 (+20%) seconds.
+
+In applications where there are multiple aggregated values, this jitter has a side-effect that sometimes you can see fewer or more aggregated values than expected. The missing values are not lost, they will be sent correctly in the next message.
+
+This jitter is not applied to **events** like button presses or input changes. They report immediately.
+
 ## Shell Commands
 
 Apart from the commands mentioned above, the shell offers many more commands. They can be listed using the `help` command.