add Low-Power demo

esp8266 · devyte · Feb 2, 2020 · Jan 6, 2020 · Jan 6, 2020 · Jan 9, 2020
commit 841fa1b9e89bb206990323e007921f0a17bf77db
diff --git a/libraries/esp8266/examples/LowPowerDemo/LowPowerDemo.ino b/libraries/esp8266/examples/LowPowerDemo/LowPowerDemo.ino
@@ -59,18 +59,18 @@ ADC_MODE(ADC_VCC);  // allows you to monitor the internal VCC level; it varies w
 // don't connect anything to the analog input pin(s)!
 
 // enter your WiFi configuration below
-const char* AP_SSID = "tryagain";  // your router's SSID here
-const char* AP_PASS = "093774c242ccb21a3485";  // your router's password here
+const char* AP_SSID = "your_SSID";  // your router's SSID here
+const char* AP_PASS = "your_password";  // your router's password here
 IPAddress staticIP(0, 0, 0, 0); // parameters below are for your static IP address, if used
 IPAddress gateway(0, 0, 0, 0);
 IPAddress subnet(0, 0, 0, 0);
 IPAddress dns1(0, 0, 0, 0);
 IPAddress dns2(0, 0, 0, 0);
-uint32_t wifiTimeout = 25E3;  // 25 second timeout on the WiFi connection
+uint32_t wifiTimeout = 30E3;  // 30 second timeout on the WiFi connection
 
-#define testPoint 4  // D2/GPIO4 used to track the timing of several test cycles, entirely optional
+//#define testPoint 4  // D2/GPIO4 used to track the timing of several test cycles, optional
 
-// This structure will be stored in RTC memory to remember the reset count (number of Deep Sleeps).
+// This structure is stored in RTC memory to remember the reset count (number of Deep Sleeps).
 // First field is CRC32, which is calculated based on the rest of the structure contents.
 // Any fields can go after the CRC32.  The structure must be 4-byte aligned.
 struct {
@@ -89,6 +89,8 @@ void wakeupCallback() {  // unlike ISRs, you can do a print() from a callback fu
 #ifdef testPoint
   digitalWrite(testPoint, LOW);  // testPoint tracks latency from WAKE_UP_PIN LOW to testPoint LOW
 #endif
+  Serial.print(F("millis() = ")); // show that RTC / millis() is slowed in Forced Light Sleep
+  Serial.println(millis());
   Serial.println(F("Woke from Forced Light Sleep - this is the callback"));
 }
 
@@ -119,6 +121,10 @@ void setup() {
       resetCount = rtcData.data[3];  // read the previous reset count
     }
   }
+  if  (resetCount == 1) {  // show that millis() is cleared across Deep Sleep reset
+    Serial.print(F("millis() = "));
+    Serial.println(millis());
+  }
 }  // end of setup()
 
 void loop() {
@@ -128,7 +134,7 @@ void loop() {
     runTest3();
     runTest4();
     runTest5();
-    runTest6();  // first Deep Sleep test, all these end with a RESET
+    runTest6();  // first Deep Sleep test, all of these end with a RESET
   }
   if (resetCount < 4) {
     initWiFi();
@@ -200,7 +206,7 @@ void runTest4() {
   WiFi.forceSleepWake();  // reconnect with previous STA mode and connection settings
   uint32_t wifiStart = millis();
   while ((!WiFi.localIP()) && (millis() - wifiStart < wifiTimeout)) {
-    delay(50);
+    yield();
   }
   if (WiFi.localIP()) {  // won't go into Automatic Sleep without an active WiFi connection
     float volts = ESP.getVcc();
@@ -221,12 +227,14 @@ void runTest5() {
   yield();
   digitalWrite(LED, HIGH);  // turn the LED off so they know the CPU isn't running
 #ifdef testPoint
-  digitalWrite(testPoint, HIGH);  
+  digitalWrite(testPoint, HIGH);
   // testPoint LOW in callback tracks latency from WAKE_UP_PIN LOW to testPoint LOW
 #endif
   float volts = ESP.getVcc();
   Serial.printf("The internal VCC reads %1.3f volts\n", volts / 1000);
   Serial.println(F("CPU going to sleep, pull WAKE_UP_PIN low to wake it (press the button)"));
+  Serial.print(F("millis() = "));
+  Serial.println(millis());
   Serial.flush();  // needs a delay(100) or Serial.flush() else it doesn't print the whole message
   wifi_fpm_set_sleep_type(LIGHT_SLEEP_T);
   gpio_pin_wakeup_enable(GPIO_ID_PIN(WAKE_UP_PIN), GPIO_PIN_INTR_LOLEVEL);
@@ -256,6 +264,8 @@ void runTest6() {
   //WiFi.mode(WIFI_SHUTDOWN);  // Forced Modem Sleep for a more Instant Deep Sleep, and no long
   // RFCAL as it goes into Deep Sleep
   Serial.println(F("going into Deep Sleep now..."));
+  Serial.print(F("millis() = "));
+  Serial.println(millis());
   Serial.flush();  // needs a delay(10) or Serial.flush() else it doesn't print the whole message
 #ifdef testPoint
   digitalWrite(testPoint, HIGH);  // testPoint set HIGH to track Deep Sleep period, cleared at startup()
@@ -329,7 +339,7 @@ void runTest9() {
 
 void resetTests() {
   resetCount = 5;  // start all over: do ESP.restart to insure a clean starting state
-    // 
+  //
   updateRTC();  // save the current test state in RTC memory
   float volts = ESP.getVcc();
   Serial.printf("The internal VCC reads %1.3f volts\n", volts / 1000);
@@ -338,7 +348,6 @@ void resetTests() {
   ESP.restart();
 }
 
-
 void waitPushbutton(bool usesDelay, unsigned int delayTime) {  // loop until they press the button
   // note: 2 different modes, as 3 of the power saving modes need a delay() to activate fully
   if (!usesDelay) {  // quick interception of button press, no delay() used
@@ -393,19 +402,24 @@ void initWiFi() {
   DEBUG_PRINTLN(WiFi.macAddress());
   uint32_t wifiStart = millis();
   while ((WiFi.status() != WL_CONNECTED) && (millis() - wifiStart < wifiTimeout)) {
-    delay(50);
+    yield();
   }
   if (WiFi.status() == WL_CONNECTED) {
     DEBUG_PRINTLN(F("WiFi connected"));
   } else {
     Serial.println(F("WiFi timed out and didn't connect"));
   }
-  while (!WiFi.localIP() && (WiFi.status() == WL_CONNECTED)) {
-    delay(50);
+  wifiStart = millis();
+  while ((!WiFi.localIP() && (WiFi.status() == WL_CONNECTED)) && (millis() - wifiStart < wifiTimeout)) {
+    yield();
   }
   WiFi.setAutoReconnect(true);
-  DEBUG_PRINT(F("WiFi Gateway IP: "));
-  DEBUG_PRINTLN(WiFi.gatewayIP());
-  DEBUG_PRINT(F("my IP address: "));
-  DEBUG_PRINTLN(WiFi.localIP());
+  if (WiFi.localIP()) {
+    DEBUG_PRINT(F("WiFi Gateway IP: "));
+    DEBUG_PRINTLN(WiFi.gatewayIP());
+    DEBUG_PRINT(F("my IP address: "));
+    DEBUG_PRINTLN(WiFi.localIP());
+  } else {
+    DEBUG_PRINTLN(F("IP addresses not acquired"));
+  }
 }
diff --git a/libraries/esp8266/examples/LowPowerDemo/README.md b/libraries/esp8266/examples/LowPowerDemo/README.md
@@ -58,11 +58,11 @@ Turns off the modem (losing the connection), and reducing the amperage by > 50 m
 
 ### Test 4 - Automatic Light Sleep
 
-Like Automatic Modem Sleep, with similar restrictions.  Once configured it's immediately active when a connection is established.  During periods of long delay() the amperage can drop to ~ 3 mA average.  In a network with sparse traffic you might get something near 2-5 mA amperage.  The LED blinks more slowly during this test as it's doing delay(350) to get the modem to sleep.  With delay() times shorter than the DTIM beacon interval (100 mS beacons for these tests) the modem only goes into Automatic Modem Sleep, and with a longer delay() it will go more fully into Automatic Light Sleep.
+Like Automatic Modem Sleep, with similar restrictions.  Once configured it's immediately active when a connection is established.  During periods of long delay() the amperage can drop to ~ 3 mA average.  In a network with sparse traffic you might get something near 2-5 mA amperage.  The LED blinks more slowly during this test as it's doing delay(350) to get the modem to sleep.  With delay() times shorter than the DTIM beacon interval (100 mS beacons for these tests) the modem only goes into Automatic Modem Sleep, and with a longer delay() it will go more fully into Automatic Light Sleep.  Although the CPU clock is cycling on and off to achieve low power, the RTC is still running so millis() and micros() are correct.
 
 ### Test 5 - Forced Light Sleep
 
-Similar to Deep Sleep, but without the timer.  The chip sleeps at 0.4 mA amperage until it is woken by an external interrupt.  The only allowed interrupts are high level and low level; edge interrupts won't work.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using Forced Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 5 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter Forced Light Sleep so you will need to re-initialize it if you are using WiFi.
+Similar to Deep Sleep, but without the timer.  The chip sleeps at 0.4 mA amperage until it is woken by an external interrupt.  The only allowed interrupts are high level and low level; edge interrupts won't work.  If you have a design that needs to be woken frequently (more often than every 2 seconds) then you should consider using Forced Light Sleep.  For sleep periods longer than 2 seconds, Deep Sleep will be more energy efficient.  The chip wakes after an interrupt in about 5 to 5.5 mS (regardless of CPU speed), but WiFi was turned off to enter Forced Light Sleep so you will need to re-initialize it if you are using WiFi.  The RTC is slowed so millis() and micros() are also slowed during Forced Light Sleep.
 
 ### Test 6 - Deep Sleep, wake with RF_DEFAULT