blink the led very briefly every 5 secs while in light sleep

TODO.md

@@ -2,12 +2,10 @@
 
 Items to complete before the first alpha release.
 
-* implement sleep state machine
+* scrolling between screens based on press is busted
+* have state machine properly enter deep sleep based on loss of mesh and phone comms
 * have gps implement canSleep(), print nmea for debugging and discard buffers on the way into sleep
 * implement CustomRF95::canSleep
-* make gps prevent light sleep if we are waiting for data
-* wake from light sleep as needed for our next scheduled periodic task (needed for gps position broadcasts etc)
-* turn bluetooth off based on our sleep policy
 * if the phone doesn't read fromradio mailbox within X seconds, assume the phone is gone and we can stop queing location msgs 
 for it (because it will redownload the nodedb when it comes back)
 * don't enter light sleep while the screen is on
@@ -25,6 +23,7 @@ for it (because it will redownload the nodedb when it comes back)
 
 Items to complete before the first beta release.
 
+* use gps sleep mode instead of killing its power (to allow fast position when we wake)
 * leave lora receiver always on
 * rx signal measurements -3 marginal, -9 bad, 10 great, -10 means almost unusable.  So scale this into % signal strength.  preferably as a graph, with an X indicating loss of comms.  
 * assign every "channel" a random shared 8 bit sync word (per 4.2.13.6 of datasheet) - use that word to filter packets before even checking CRC.  This will ensure our CPU will only wake for packets on our "channel"  
@@ -163,3 +162,6 @@ Items after the first final candidate release.
 * support non US frequencies
 * send pr https://github.com/ThingPulse/esp8266-oled-ssd1306 to tell them about this project
 * document rules for sleep wrt lora/bluetooth/screen/gps.  also: if I have text messages (only) for the phone, then give a few seconds in the hopes BLE can get it across before we have to go back to sleep.
+* wake from light sleep as needed for our next scheduled periodic task (needed for gps position broadcasts etc)
+* turn bluetooth off based on our sleep policy
+* blink LED while in LS sleep mode

src/GPS.cpp

@@ -2,6 +2,7 @@
 #include "GPS.h"
 #include "time.h"
 #include <sys/time.h>
+#include "configuration.h"
 
 // stuff that really should be in in the instance instead...
 HardwareSerial _serial_gps(GPS_SERIAL_NUM);
@@ -98,12 +99,15 @@ void GPS::doTask()
     while (_serial_gps.available())
     {
         encode(_serial_gps.read());
+        // DEBUG_MSG("Got GPS response\n");
     }
 
     if (!timeSetFromGPS && time.isValid() && date.isValid())
     {
         struct timeval tv;
 
+        DEBUG_MSG("Got time from GPS\n");
+
         /* Convert to unix time 
         The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z). 
         */

src/PowerFSM.cpp

@@ -43,11 +43,27 @@ static void lsEnter()
 
 static void lsIdle()
 {
-    doLightSleep(radioConfig.preferences.ls_secs * 1000LL);
+    uint32_t secsSlept = 0;
+    esp_sleep_source_t wakeCause = ESP_SLEEP_WAKEUP_UNDEFINED;
 
-    // FIXME - blink led when we occasionally wake from timer, then go back to light sleep
+    while (secsSlept < radioConfig.preferences.ls_secs)
+    {
+        // Briefly come out of sleep long enough to blink the led once every few seconds
+        uint32_t sleepTime = 5;
 
-    // Regardless of why we woke (for now) just transition to NB
+        setLed(false); // Never leave led on while in light sleep
+        wakeCause = doLightSleep(sleepTime * 1000LL);
+        if (wakeCause != ESP_SLEEP_WAKEUP_TIMER)
+            break;
+
+        setLed(true); // briefly turn on led
+        doLightSleep(1);
+        if (wakeCause != ESP_SLEEP_WAKEUP_TIMER)
+            break;
+    }
+    setLed(false);
+
+    // Regardless of why we woke (for now) just transition to NB (and that state will handle stuff like IRQs etc)
     powerFSM.trigger(EVENT_WAKE_TIMER);
 }
 

src/screen.cpp

@@ -651,13 +651,6 @@ void Screen::doTask()
                 nodeDB.updateGUI = false;
                 nodeDB.updateTextMessage = false;
             }
-
-/*
-            if (millis() - lastPressMs > SCREEN_SLEEP_MS)
-            {
-                DEBUG_MSG("screen timeout, turn it off for now...\n");
-                screen.setOn(false);
-            } */
         }
     }
 

src/sleep.cpp

@@ -209,11 +209,11 @@ void setBluetoothEnable(bool on)
  */
 esp_sleep_wakeup_cause_t doLightSleep(uint64_t sleepMsec) // FIXME, use a more reasonable default
 {
-  DEBUG_MSG("Enter light sleep\n");
+  //DEBUG_MSG("Enter light sleep\n");
   uint64_t sleepUsec = sleepMsec * 1000LL;
 
+  Serial.flush(); // send all our characters before we stop cpu clock
   setBluetoothEnable(false); // has to be off before calling light sleep
-  setLed(false);      // Never leave led on while in light sleep
 
   // NOTE! ESP docs say we must disable bluetooth and wifi before light sleep
 
@@ -228,7 +228,7 @@ esp_sleep_wakeup_cause_t doLightSleep(uint64_t sleepMsec) // FIXME, use a more r
   assert(esp_sleep_enable_gpio_wakeup() == ESP_OK);
   assert(esp_sleep_enable_timer_wakeup(sleepUsec) == ESP_OK);
   assert(esp_light_sleep_start() == ESP_OK);
-  DEBUG_MSG("Exit light sleep\n");
+  //DEBUG_MSG("Exit light sleep\n");
   return esp_sleep_get_wakeup_cause();
 }