Wait for Event / Best Idle state

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For Gen 3 devices what are people using for an idle state?
My battery application requires reasonably quick response <1min but i also need to be power conscious.
It seems the deep sleep stuff requires long periods to reconnect and misses many cloud functions.

Can I use the usual ARM Wait For Interrupt (__WFI) or Wait For Event (__WFE) to reduce power just a bit? Or is this already part of the RTOS?


take look at this thread

It covers a lot of ground and the last post provides power savings of the varies modes


I did some tests to see what would happen. Using a 10s average though a 1ohm resistor on the LI+ I got the following results:


void setup() {

void loop() {
    // Enter System ON sleep mode

Without the Wait code: (3.96V x 4.07mA) 16.12mW
With the Wait code: (3.96V x 1.48mA) 5.86mW

I’m really surprised this isn’t already in the RTOS idle task. Anyway. hope this helps people get more battery life without sacrificing response.


Does this maintain particle cloud connection in this state?


So far it seems a bit sketchy. The WFE seems to mess with obtaining a cloud connection. But once connected its seems ok. Reponds to pings and functions as normal.

I might not both for the 8mW of power savings the potential for problems is too much. I think a wait stop needs to be incorporated to the RTOS idle task for less obtrusion.

Using this sketch on an idling boron I got these results over 60s average.
Without the Wait code: (3.92V x 48mA) 188.16mW
With the Wait code: (3.92V x 46mA) 180.3mW


LEDSystemTheme theme; // Enable custom theme

void setup() {
    theme.setColor(LED_SIGNAL_CLOUD_CONNECTED, 0x00000000); // Set LED_SIGNAL_NETWORK_ON to no color
	theme.apply(); // Apply theme settings 

void loop() {
    if(Particle.connected() && millis() > 60000){


Bump, I was wondering if any of the Particle team are working on adding a cpu wait state in the main loop? Or at least in the delay loop to reduce power?