LIGHT_SLEEP HOW ?

[donnib]

Hi,
How is it possible to light sleep with arduino framework on the ESP8266, i know how to deepsleep and it works but i am interested to do LIGHT_SLEEP so i can benefit from "low power" equal to 0.5mA and have GPIO wake up enabled with gpio_pin_wakeup_enable.

I can't seem to find examples how to do this, anyone tried it ?

donnib

Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.

[stevescot]

Here's what I currently have, it runs, but does not go to Light_sleep.

---

#include "ESP8266WiFi.h"
#include "gpio.h"
extern "C" {
#include "user_interface.h"
  uint16 readvdd33(void);
  bool wifi_set_sleep_type(sleep_type_t);
  sleep_type_t wifi_get_sleep_type(void);
}
bool sleep = false;

int switchPin = 2;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("before Sleep");
  goToLightSleep();
  Serial.println("Woken up");
}

void loop() {
  // put your main code here, to run repeatedly:

}

void goToLightSleep()
{
  if (!sleep)
  {
    Serial.println("switching off Wifi Modem and CPU");
    //stop any clients
    ///thisclient.stop();
    delay(1000);
    wifi_set_sleep_type(LIGHT_SLEEP_T);
    WiFi.disconnect();
    WiFi.mode(WIFI_OFF);
    // how do we call this: 
    //gpio_pin_wakeup_enable(GPIO_ID_PIN(switchPin),GPIO_PIN_INTR_NEGEDGE);
    wifi_fpm_open();
    wifi_fpm_do_sleep(26843455);
    //if(WiFi.forceSleepBegin(26843455)) sleep = true;
  }
}

[antelder]

From what i understand light sleep is on by default but only happens when the ESP is in station mode and connected to an access point. The default mode is WIFI_AP_STA so you need to call WiFi.mode(WIFI_STA) and then connect to an access point. I did test this out and it did seem to work and reduce power consumption to a bit less than 1 mA during inactivity, but that was quite a while back now and i've not verified it still works with the lastest ESP/Arduino code and SDK.

[stevescot]

antelder - I think you might be talking about modem_sleep where power use goes down to 20mA, - that is on by default but has no effect for me, so I force modem sleep when I don't need wifi.

Light_sleep requires a pin interrupt to wake it, and switches off the CPU and WiFi, so it can't wake itself,

http://bbs.espressif.com/viewtopic.php?t=133

[antelder]

I don't think so but i admit all this area can be confusing and is not well documented so i may be mistaken. However, i'm pretty sure i've tried both those and what i described above is how i got light sleep to work and the power consumption was matching what they say it should be at a bit under 1 mA. Where have you seen it said that light sleep requires a pin interrupt to wake up?

[Links2004]

Modem sleep is working an implemented in staring / git.
usage:
when you want to sleep (disable WiFi):

WiFi.forceSleepBegin();

and to enable WiFi again:

WiFi.forceSleepWake();

more info starting here:
#460 (comment)
#460

[donnib]

@stevescot yes exactly what i am looking for. I can't find somebody that got this to work yet.

[torntrousers]

I dug up the old sketch i had for testing light sleep and tried it again with the current 2.0.0 release. WIth this sketch light sleep definately only seems to kick in when in station mode and Wifi is connected and i see a minimum current of about 1 mA. Its a bit hard to see the current use on a multimeter as the current dances around (which is what you'd expect with light sleep, right?, as it keeps waking up every 300 milliseconds or so) but its most of the time showing well under 10mA:

#include <ESP8266WiFi.h>
extern "C" {
  #include "user_interface.h"
}

const char* ssid = "BTHub5-72W5";
const char* password = "xxxxxxxxxx";

void setup() {
  Serial.begin(115200);
  Serial.println();
}

void loop() {

  initWifi();

  Serial.println("Light sleep:");
  wifi_set_sleep_type(LIGHT_SLEEP_T);
  doDelays();

  Serial.println("None sleep:");
  wifi_set_sleep_type(NONE_SLEEP_T);
  doDelays();

  WiFi.disconnect();
  Serial.print("WiFi disconnected, IP address: "); Serial.println(WiFi.localIP());
  Serial.println("Light sleep:");
  wifi_set_sleep_type(LIGHT_SLEEP_T);
  doDelays();

}

void doDelays() {
  Serial.println("Yield for 20 sec");
  long endMs = millis() + 20000;
  while (millis() < endMs) {
     yield();
  }

  Serial.println("Delay for 20 sec");
  delay(20000);
}

void initWifi() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while ((WiFi.status() != WL_CONNECTED)) {
     delay(500);
     Serial.print(".");
  }
  Serial.println("");
  Serial.print("WiFi connected, IP address: "); Serial.println(WiFi.localIP());
}

[stevescot]

That sounds great - will try it...

[Links2004]

Note: sleep in AP mode is not possible, since the connected client can send something to any time.
in STA mode the WiFi standard allows the client to sleep (the ESP)

[stevescot]

Ran this script findings were:

with light_sleep, when delay is called the modem, and cpu will shut down (going down to 1mA and below for small periods between beacons, )
however - the yield time shows 70mA

[stevescot]

Setting to modem_sleep - still when delay is called then power drops to 20mA, given that sleep only happens when you have called delay (then you are not using the CPU)- no reason not to set light sleep.

[WereCatf]

I am sorry for butting in on the conversation, but I would also be interested in learning how to make use of light-sleep. I just did some testing I can get modem-sleep to work just fine, but light-sleep only works when the ESP is actively connected to the WIFI-network -- I can't get light-sleep to work if I disconnect from the network.

If the ESP is connected to the network the current-draw keeps jumping up and down during delay() (it momentarily drops well below 10mA, so it is definitely working at times) and overall current-draw won't be anywhere near Espressif's claims. On the other hand, disconnecting from the network and forcing modem-sleep works fine -- current-draw stays stable <17mA during delay(). Disconnecting from the network and trying to enter light-sleep either draws current as if the was no power-management at all enabled, ie. >50mA or current-draw stays at <17mA if I force modem-sleep after disconnect.

Is it even possible to get light-sleep to work when disconnected so as to get power-draw down during longer periods of sleep?

[donnib]

I still don't get it, how can light_sleep work without having the GPIO
enable wake ? In the manual
http://russ.russmathis.com/wp-content/uploads/2015/09/9B-ESP8266__Sleep__Function-Description__EN_v1.0.pdf
it is stated that the CPU is in suspend and the clock is off so one need to
wake up the device with GPIO out of light_sleep or ?

On Mon, Jan 11, 2016 at 12:47 PM, WereCatf notifications@github.com wrote:

I am sorry for butting in on the conversation, but I would also be
interested in learning how to make use of light-sleep. I just did some
testing I can get modem-sleep to work just fine, but light-sleep only works
when the ESP is actively connected to the WIFI-network -- I can't get
light-sleep to work if I disconnect from the network.

If the ESP is connected to the network the current-draw keeps jumping up
and down during delay() and overall current-draw won't be anywhere near
Espressif's claims. On the other hand, disconnecting from the network and
forcing modem-sleep works fine -- current-draw stays stable <17mA during
delay(). Disconnecting from the network and trying to enter light-sleep
either draws current as if the was no power-management at all enabled, ie.

50mA or current-draw stays at <17mA if I force modem-sleep after
disconnect.

Is it even possible to get light-sleep to work when disconnected so as to
get power-draw down during longer periods of sleep?

—
Reply to this email directly or view it on GitHub
#1381 (comment).

[stevescot]

Yeah that confused me - my assumption is that light sleep as implemented by the core code uses the real-time clock to do an interrupt - so it is not running code and not using WiFi during these periods. However if you manually put the chip into light sleep then you will need to generate an interrupt to wake. That is all empirical - haven't seen documents to tell me that its just what seems to make sense.

[WereCatf]

@donnib: The PDF says "Under the light-sleep mode, the CPU will not respond to the signal and interrupt from the peripheral hardware interface under the pause state. Therefore, the ESP8266 need to be waked up via external GPIO, and the wake process is less than 3 ms."

I read that as them saying that any interrupts you've attached to GPIO-pin state-changes won't work under light-sleep, but you can designate one GPIO-pin that the ESP will monitor in order to wake up from light-sleep and then it will be able to handle those interrupts. Internal mechanisms based on WIFI and RTC, however, will keep running and working even during light-sleep.

My interpretation may be completely off the base, but that's how I read it.