Workaround for Gen 3 devices not connecting to the cloud in non-automatic threaded mode

[sergeuz]

Problem

The system loop on Gen 3 modifies the value of the SPARK_WLAN_SLEEP flag, which may prevent Particle.connect() from initiating a connection to the cloud when the app is running in threaded mode.

Solution

Do not call network_off() in the system loop if SPARK_WLAN_SLEEP is set but there's no active or ongoing network connection.

Note that this is more a workaround rather than a solution. Ideally, we need to refactor the system state management logic so that SPARK_WLAN_SLEEP (or its equivalent) only controls the "administrative" state of the networking subsystem, i.e. whether the user wants networking to be enabled, rather than both the administrative state and the actual one.

Steps to Test

The easiest way to reproduce this issue is to introduce artificial delays in the system loop:

1. Apply this diff to develop, build and flash the system firmware and the example application to a Gen 3 device.
2. Verify that the device is breathing white despite that Particle.connect() has been called in setup().
3. Check out this branch and reintroduce the same delay in the system loop.
4. Verify that the device running the same application is connecting to the cloud.

Example App

#include "application.h"

SYSTEM_MODE(SEMI_AUTOMATIC)
SYSTEM_THREAD(ENABLED)

void setup() {
    HAL_Delay_Milliseconds(250);
    Particle.connect();
}

void loop() {
}

References

• [ch59176]