Merge branch 'geeksville-master'

.gitignore

@@ -1,3 +1,12 @@
-
+.pio
 main/configuration.h
 main/credentials.h
+credentials-private.h
+
+# ignore vscode IDE settings files
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace

.vscode/extensions.json

@@ -0,0 +1,7 @@
+{
+	// See http://go.microsoft.com/fwlink/?LinkId=827846
+	// for the documentation about the extensions.json format
+	"recommendations": [
+		"platformio.platformio-ide"
+	]
+}

.vscode/launch.json

@@ -0,0 +1,32 @@
+// AUTOMATICALLY GENERATED FILE. PLEASE DO NOT MODIFY IT MANUALLY
+
+// PIO Unified Debugger
+//
+// Documentation: https://docs.platformio.org/page/plus/debugging.html
+// Configuration: https://docs.platformio.org/page/projectconf/section_env_debug.html
+
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "platformio-debug",
+            "request": "launch",
+            "name": "PIO Debug",
+            "executable": "/home/kevinh/development/lora/ttgo-tbeam-ttn-tracker/.pio/build/esp32/firmware.elf",
+            "toolchainBinDir": "/home/kevinh/.platformio/packages/toolchain-xtensa32/bin",
+            "preLaunchTask": {
+                "type": "PlatformIO",
+                "task": "Pre-Debug"
+            },
+            "internalConsoleOptions": "openOnSessionStart"
+        },
+        {
+            "type": "platformio-debug",
+            "request": "launch",
+            "name": "PIO Debug (skip Pre-Debug)",
+            "executable": "/home/kevinh/development/lora/ttgo-tbeam-ttn-tracker/.pio/build/esp32/firmware.elf",
+            "toolchainBinDir": "/home/kevinh/.platformio/packages/toolchain-xtensa32/bin",
+            "internalConsoleOptions": "openOnSessionStart"
+        }
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,15 @@
+{
+    "files.associations": {
+        "*.tcc": "cpp",
+        "deque": "cpp",
+        "string": "cpp",
+        "unordered_map": "cpp",
+        "unordered_set": "cpp",
+        "vector": "cpp",
+        "fstream": "cpp",
+        "iomanip": "cpp",
+        "limits": "cpp",
+        "sstream": "cpp",
+        "system_error": "cpp"
+    }
+}

main/configuration.h

@@ -40,8 +40,8 @@ void ttn_register(void (*callback)(uint8_t message));
 // -----------------------------------------------------------------------------
 
 // Select which T-Beam board is being used. Only uncomment one.
-#define T_BEAM_V07  // AKA Rev0 (first board released)
+// #define T_BEAM_V07  // AKA Rev0 (first board released)
-//#define T_BEAM_V10  // AKA Rev1 (second board released)
+#define T_BEAM_V10  // AKA Rev1 (second board released)
 
 // Select the payload format. Change on TTN as well. Only uncomment one.
 #define PAYLOAD_USE_FULL
@@ -56,15 +56,18 @@ void ttn_register(void (*callback)(uint8_t message));
 
 #define DEBUG_PORT              Serial      // Serial debug port
 #define SERIAL_BAUD             115200      // Serial debug baud rate
-#define SLEEP_BETWEEN_MESSAGES  0           // Do sleep between messages
+#define SLEEP_BETWEEN_MESSAGES  true        // Do sleep between messages
-#define SEND_INTERVAL           10000       // Sleep for these many millis
+#define SEND_INTERVAL           (5 * 60 * 1000) // Sleep for these many millis
 #define MESSAGE_TO_SLEEP_DELAY  5000        // Time after message before going to sleep
 #define LOGO_DELAY              5000        // Time to show logo on first boot
 #define LORAWAN_PORT            10          // Port the messages will be sent to
 #define LORAWAN_CONFIRMED_EVERY 0           // Send confirmed message every these many messages (0 means never)
-#define LORAWAN_SF              DR_SF7      // Spreading factor
+#define LORAWAN_SF              DR_SF10     // Spreading factor (recommended DR_SF7 for ttn network map purposes, DR_SF10 works for slow moving trackers)
 #define LORAWAN_ADR             0           // Enable ADR
-#define GPS_WAIT_FOR_LOCK       5000        // Wait 5s after every boot for GPS lock
+#define REQUIRE_RADIO           true        // If true, we will fail to start if the radio is not found
+
+// If not defined, we will wait for lock forever
+#define GPS_WAIT_FOR_LOCK       (60 * 1000)  // Wait after every boot for GPS lock (may need longer than 5s because we turned the gps off during deep sleep)
 
 // -----------------------------------------------------------------------------
 // DEBUG
@@ -91,9 +94,9 @@ void ttn_register(void (*callback)(uint8_t message));
 
 #define I2C_SDA         21
 #define I2C_SCL         22
-#define LED_PIN         14
 
 #if defined(T_BEAM_V07)
+#define LED_PIN         14
 #define BUTTON_PIN      39
 #elif defined(T_BEAM_V10)
 #define BUTTON_PIN      38
@@ -129,16 +132,20 @@ void ttn_register(void (*callback)(uint8_t message));
 #define MISO_GPIO       19
 #define MOSI_GPIO       27
 #define NSS_GPIO        18
+#if defined(T_BEAM_V10)
+#define RESET_GPIO      14
+#else
 #define RESET_GPIO      23
+#endif
 #define DIO0_GPIO       26
-#define DIO1_GPIO       33
+#define DIO1_GPIO       33 // Note: not really used on this board
-#define DIO2_GPIO       32
+#define DIO2_GPIO       32 // Note: not really used on this board
 
 // -----------------------------------------------------------------------------
 // AXP192 (Rev1-specific options)
 // -----------------------------------------------------------------------------
 
-#define AXP192_SLAVE_ADDRESS  0x34
+// #define AXP192_SLAVE_ADDRESS  0x34 // Now defined in axp20x.h
 #define GPS_POWER_CTRL_CH     3
 #define LORA_POWER_CTRL_CH    2
 #define PMU_IRQ               35

main/credentials.h

@@ -7,8 +7,8 @@ Credentials file
 #pragma once
 
 // Only one of these settings must be defined
-#define USE_ABP
+//#define USE_ABP
-//#define USE_OTAA
+#define USE_OTAA
 
 #ifdef USE_ABP
 
@@ -24,6 +24,9 @@ Credentials file
 
 #ifdef USE_OTAA
 
+#if 0
+    // copy these variables to ../credentials-private.h and customize with your secret appkey.
+    
     // This EUI must be in little-endian format, so least-significant-byte
     // first. When copying an EUI from ttnctl output, this means to reverse
     // the bytes. For TTN issued EUIs the last bytes should be 0x00, 0x00,
@@ -31,12 +34,14 @@ Credentials file
     static const u1_t PROGMEM APPEUI[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
 
     // This should also be in little endian format, see above.
-    static const u1_t PROGMEM DEVEUI[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    // Note: You do not need to set this field, if unset it will be generated automatically based on the device macaddr
+    static u1_t DEVEUI[8]  = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
 
     // This key should be in big endian format (or, since it is not really a
     // number but a block of memory, endianness does not really apply). In
     // practice, a key taken from ttnctl can be copied as-is.
     // The key shown here is the semtech default key.
     static const u1_t PROGMEM APPKEY[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+#endif 
 
 #endif

main/gps.ino

@@ -80,7 +80,7 @@ static void gps_loop() {
         Serial.println(t);
         sprintf(t, "Lng: %f", _gps.location.lng());
         Serial.println(t);
-        sprintf(t, "Alt: %f", altitudeGps);
+        sprintf(t, "Alt: %d", altitudeGps);
         Serial.println(t);
         sprintf(t, "Hdop: %d", hdopGps);
         Serial.println(t);

main/main.ino

@@ -36,22 +36,35 @@ String baChStatus = "No charging";
 bool ssd1306_found = false;
 bool axp192_found = false;
 
-// Message counter, stored in RTC memory, survives deep sleep
+bool packetSent, packetQueued;
-RTC_DATA_ATTR uint32_t count = 0;
 
 #if defined(PAYLOAD_USE_FULL)
   // includes number of satellites and accuracy
-  uint8_t txBuffer[10];
+  static uint8_t txBuffer[10];
 #elif defined(PAYLOAD_USE_CAYENNE)
   // CAYENNE DF
   static uint8_t txBuffer[11] = {0x03, 0x88, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
 #endif
 
+// deep sleep support
+RTC_DATA_ATTR int bootCount = 0;
+esp_sleep_source_t wakeCause; // the reason we booted this time
+
 // -----------------------------------------------------------------------------
 // Application
 // -----------------------------------------------------------------------------
 
-void send() {
+void buildPacket(uint8_t txBuffer[]); // needed for platformio
+
+/**
+ * If we have a valid position send it to the server.
+ * @return true if we decided to send.
+ */
+bool trySend() {
+  packetSent = false;
+  // We also wait for altitude being not exactly zero, because the GPS chip generates a bogus 0 alt report when first powered on
+  if (0 < gps_hdop() && gps_hdop() < 50 && gps_latitude() != 0 && gps_longitude() != 0 && gps_altitude() != 0)
+  {
     char buffer[40];
     snprintf(buffer, sizeof(buffer), "Latitude: %10.6f\n", gps_latitude());
     screen_print(buffer);
@@ -68,15 +81,54 @@ void send() {
     bool confirmed = false;
 #endif
 
-  ttn_cnt(count);
+    packetQueued = true;
     ttn_send(txBuffer, sizeof(txBuffer), LORAWAN_PORT, confirmed);
-
+    return true;
-  count++;
   }
+  else {
+    return false;
+  }
+}
+
+
+void doDeepSleep(uint64_t msecToWake)
+{
+    Serial.printf("Entering deep sleep for %llu seconds\n", msecToWake / 1000);
+
+    // not using wifi yet, but once we are this is needed to shutoff the radio hw
+    // esp_wifi_stop();
+
+    screen_off(); // datasheet says this will draw only 10ua
+    LMIC_shutdown(); // cleanly shutdown the radio
+    
+    if(axp192_found) {
+        // turn on after initial testing with real hardware
+        axp.setPowerOutPut(AXP192_LDO2, AXP202_OFF); // LORA radio
+        axp.setPowerOutPut(AXP192_LDO3, AXP202_OFF); // GPS main power
+    }
+
+    // FIXME - use an external 10k pulldown so we can leave the RTC peripherals powered off
+    // until then we need the following lines
+    esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
+
+    // Only GPIOs which are have RTC functionality can be used in this bit map: 0,2,4,12-15,25-27,32-39.
+    uint64_t gpioMask = (1ULL << BUTTON_PIN);
+
+    // FIXME change polarity so we can wake on ANY_HIGH instead - that would allow us to use all three buttons (instead of just the first)
+    gpio_pullup_en((gpio_num_t) BUTTON_PIN);
+
+    esp_sleep_enable_ext1_wakeup(gpioMask, ESP_EXT1_WAKEUP_ALL_LOW);
+
+    esp_sleep_enable_timer_wakeup(msecToWake * 1000ULL); // call expects usecs
+    esp_deep_sleep_start();                              // TBD mA sleep current (battery)
+}
+
 
 void sleep() {
 #if SLEEP_BETWEEN_MESSAGES
 
+  // If the user has a screen, tell them we are about to sleep
+  if(ssd1306_found) {
     // Show the going to sleep message on the screen
     char buffer[20];
     snprintf(buffer, sizeof(buffer), "Sleeping in %3.1fs\n", (MESSAGE_TO_SLEEP_DELAY / 1000.0));
@@ -87,6 +139,7 @@ void sleep() {
 
     // Turn off screen
     screen_off();
+    }
 
   // Set the user button to wake the board
   sleep_interrupt(BUTTON_PIN, LOW);
@@ -94,14 +147,19 @@ void sleep() {
   // We sleep for the interval between messages minus the current millis
   // this way we distribute the messages evenly every SEND_INTERVAL millis
   uint32_t sleep_for = (millis() < SEND_INTERVAL) ? SEND_INTERVAL - millis() : SEND_INTERVAL;
-  sleep_millis(sleep_for);
+  doDeepSleep(sleep_for);
 
 #endif
 }
 
+
+
+
 void callback(uint8_t message) {
   if (EV_JOINING == message) screen_print("Joining TTN...\n");
-  if (EV_JOINED == message) screen_print("TTN joined!\n");
+  if (EV_JOINED == message) {
+    screen_print("TTN joined!\n");
+  }
   if (EV_JOIN_FAILED == message) screen_print("TTN join failed\n");
   if (EV_REJOIN_FAILED == message) screen_print("TTN rejoin failed\n");
   if (EV_RESET == message) screen_print("Reset TTN connection\n");
@@ -110,9 +168,11 @@ void callback(uint8_t message) {
   if (EV_PENDING == message) screen_print("Message discarded\n");
   if (EV_QUEUED == message) screen_print("Message queued\n");
 
-  if (EV_TXCOMPLETE == message) {
+  // We only want to say 'packetSent' for our packets (not packets needed for joining)
+  if (EV_TXCOMPLETE == message && packetQueued) {
     screen_print("Message sent\n");
-    sleep();
+    packetQueued = false;
+    packetSent = true;
   }
 
   if (EV_RESPONSE == message) {
@@ -132,9 +192,7 @@ void callback(uint8_t message) {
   }
 }
 
-uint32_t get_count() {
+
-  return count;
-}
 
 void scanI2Cdevice(void)
 {
@@ -172,18 +230,18 @@ void scanI2Cdevice(void)
         Serial.println("done\n");
 }
 
-void setup() {
+/**
-  // Debug
+ * Init the power manager chip
-  #ifdef DEBUG_PORT
+ * 
-  DEBUG_PORT.begin(SERIAL_BAUD);
+ * axp192 power 
-  #endif
+    DCDC1 0.7-3.5V @ 1200mA max -> OLED // If you turn this off you'll lose comms to the axp192 because the OLED and the axp192 share the same i2c bus, instead use ssd1306 sleep mode
-
+    DCDC2 -> unused
-  delay(1000);
+    DCDC3 0.7-3.5V @ 700mA max -> ESP32 (keep this on!)
-
+    LDO1 30mA -> charges GPS backup battery // charges the tiny J13 battery by the GPS to power the GPS ram (for a couple of days), can not be turned off
-  #ifdef T_BEAM_V10
+    LDO2 200mA -> LORA
-  Wire.begin(I2C_SDA, I2C_SCL);
+    LDO3 200mA -> GPS
-  scanI2Cdevice();
+ */
-  axp192_found = true;
+void axp192Init() {
     if (axp192_found) {
         if (!axp.begin(Wire, AXP192_SLAVE_ADDRESS)) {
             Serial.println("AXP192 Begin PASS");
@@ -199,12 +257,12 @@ void setup() {
         Serial.printf("Exten: %s\n", axp.isExtenEnable() ? "ENABLE" : "DISABLE");
         Serial.println("----------------------------------------");
 
-      axp.setPowerOutPut(AXP192_LDO2, AXP202_ON);
+        axp.setPowerOutPut(AXP192_LDO2, AXP202_ON); // LORA radio
-      axp.setPowerOutPut(AXP192_LDO3, AXP202_ON);
+        axp.setPowerOutPut(AXP192_LDO3, AXP202_ON); // GPS main power
         axp.setPowerOutPut(AXP192_DCDC2, AXP202_ON);
         axp.setPowerOutPut(AXP192_EXTEN, AXP202_ON);
         axp.setPowerOutPut(AXP192_DCDC1, AXP202_ON);
-      axp.setDCDC1Voltage(3300);
+        axp.setDCDC1Voltage(3300); // for the OLED power
 
         Serial.printf("DCDC1: %s\n", axp.isDCDC1Enable() ? "ENABLE" : "DISABLE");
         Serial.printf("DCDC2: %s\n", axp.isDCDC2Enable() ? "ENABLE" : "DISABLE");
@@ -228,23 +286,58 @@ void setup() {
     } else {
         Serial.println("AXP192 not found");
     }
+}
+
+
+// Perform power on init that we do on each wake from deep sleep
+void initDeepSleep() {
+    bootCount++;
+    wakeCause = esp_sleep_get_wakeup_cause(); 
+    /* 
+    Not using yet because we are using wake on all buttons being low
+
+    wakeButtons = esp_sleep_get_ext1_wakeup_status();       // If one of these buttons is set it was the reason we woke
+    if (wakeCause == ESP_SLEEP_WAKEUP_EXT1 && !wakeButtons) // we must have been using the 'all buttons rule for waking' to support busted boards, assume button one was pressed
+        wakeButtons = ((uint64_t)1) << buttons.gpios[0];
+    */
+
+    Serial.printf("booted, wake cause %d (boot count %d)\n", wakeCause, bootCount);
+}
+
+void setup() {
+  // Debug
+  #ifdef DEBUG_PORT
+  DEBUG_PORT.begin(SERIAL_BAUD);
   #endif
 
+  initDeepSleep();
+
+  Wire.begin(I2C_SDA, I2C_SCL);
+  scanI2Cdevice();
+
+  axp192Init();
+
   // Buttons & LED
   pinMode(BUTTON_PIN, INPUT_PULLUP);
+#ifdef LED_PIN
   pinMode(LED_PIN, OUTPUT);
+#endif
 
   // Hello
   DEBUG_MSG(APP_NAME " " APP_VERSION "\n");
 
-  // Display
+  // Don't init display if we don't have one or we are waking headless due to a timer event
+  if(wakeCause == ESP_SLEEP_WAKEUP_TIMER)
+    ssd1306_found = false; // forget we even have the hardware
+
+  if(ssd1306_found)
     screen_setup();
 
   // Init GPS
   gps_setup();
 
-  // Show logo on first boot
+  // Show logo on first boot after removing battery
-  if (0 == count) {
+  if (bootCount == 0) {
     screen_print(APP_NAME " " APP_VERSION, 0, 0);
     screen_show_logo();
     screen_update();
@@ -254,17 +347,17 @@ void setup() {
   // TTN setup
   if (!ttn_setup()) {
     screen_print("[ERR] Radio module not found!\n");
+
+    if(REQUIRE_RADIO) {
       delay(MESSAGE_TO_SLEEP_DELAY);
       screen_off();
       sleep_forever();
     }
-
+  }
+  else {
     ttn_register(callback);
     ttn_join();
-  ttn_sf(LORAWAN_SF);
     ttn_adr(LORAWAN_ADR);
-  if(!LORAWAN_ADR){
-    LMIC_setLinkCheckMode(0); // Link check problematic if not using ADR. Must be set after join
   }
 }
 
@@ -273,23 +366,54 @@ void loop() {
   ttn_loop();
   screen_loop();
 
+  if(packetSent) {
+    packetSent = false;
+    sleep();
+  }
+
+  // if user presses button for more than 3 secs, discard our network prefs and reboot (FIXME, use a debounce lib instead of this boilerplate)
+  static bool wasPressed = false;
+  static uint32_t minPressMs; // what tick should we call this press long enough
+  if(!digitalRead(BUTTON_PIN)) {
+    if(!wasPressed) { // just started a new press
+      Serial.println("pressing");
+      wasPressed = true;
+      minPressMs = millis() + 3000;
+    } 
+  } else if(wasPressed) {
+    // we just did a release
+    wasPressed = false;
+    if(millis() > minPressMs) {
+      // held long enough
+      screen_print("Erasing prefs");
+      ttn_erase_prefs();
+      delay(5000); // Give some time to read the screen
+      ESP.restart();
+    }
+  }
+
   // Send every SEND_INTERVAL millis
   static uint32_t last = 0;
   static bool first = true;
   if (0 == last || millis() - last > SEND_INTERVAL) {
-    if (0 < gps_hdop() && gps_hdop() < 50 && gps_latitude() != 0 && gps_longitude() != 0) {
+    if (trySend()) {
       last = millis();
       first = false;
-      Serial.println("TRANSMITTING");
+      Serial.println("TRANSMITTED");
-      send();
     } else {
       if (first) {
         screen_print("Waiting GPS lock\n");
         first = false;
       }
+#ifdef GPS_WAIT_FOR_LOCK
       if (millis() > GPS_WAIT_FOR_LOCK) {
         sleep();
       }
+#endif
+
+      // No GPS lock yet, let the OS put the main CPU in low power mode for 100ms (or until another interrupt comes in)
+      // i.e. don't just keep spinning in loop as fast as we can.
+      delay(100);
     }
   }
 }

main/screen.ino

@@ -32,10 +32,12 @@ SSD1306Wire * display;
 uint8_t _screen_line = SCREEN_HEADER_HEIGHT - 1;
 
 void _screen_header() {
+    if(!display) return;
+
     char buffer[20];
 
     // Message count
-    snprintf(buffer, sizeof(buffer), "#%03d", get_count() % 1000);
+    snprintf(buffer, sizeof(buffer), "#%03d", ttn_get_count() % 1000);
     display->setTextAlignment(TEXT_ALIGN_LEFT);
     display->drawString(0, 2, buffer);
 
@@ -57,25 +59,36 @@ void _screen_header() {
 }
 
 void screen_show_logo() {
+    if(!display) return;
+
     uint8_t x = (display->getWidth() - TTN_IMAGE_WIDTH) / 2;
     uint8_t y = SCREEN_HEADER_HEIGHT + (display->getHeight() - SCREEN_HEADER_HEIGHT - TTN_IMAGE_HEIGHT) / 2 + 1;
     display->drawXbm(x, y, TTN_IMAGE_WIDTH, TTN_IMAGE_HEIGHT, TTN_IMAGE);
 }
 
 void screen_off() {
+    if(!display) return;
+
     display->displayOff();
 }
 
 void screen_on() {
+    if(!display) return;
+
     display->displayOn();
 }
 
 void screen_clear() {
+    if(!display) return;
+
     display->clear();
 }
 
 void screen_print(const char * text, uint8_t x, uint8_t y, uint8_t alignment) {
     DEBUG_MSG(text);
+
+    if(!display) return;
+
     display->setTextAlignment((OLEDDISPLAY_TEXT_ALIGNMENT) alignment);
     display->drawString(x, y, text);
 }
@@ -85,6 +98,9 @@ void screen_print(const char * text, uint8_t x, uint8_t y) {
 }
 
 void screen_print(const char * text) {
+    Serial.printf("Screen: %s\n", text);
+    if(!display) return;
+
     display->print(text);
     if (_screen_line + 8 > display->getHeight()) {
         // scroll
@@ -94,6 +110,7 @@ void screen_print(const char * text) {
 }
 
 void screen_update() {
+    if(display)
         display->display();
 }
 
@@ -109,6 +126,8 @@ void screen_setup() {
 }
 
 void screen_loop() {
+    if(!display) return;
+
     #ifdef T_BEAM_V10
     if (axp192_found && pmu_irq) {
         pmu_irq = false;

main/ttn.ino

@@ -27,9 +27,13 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <hal/hal.h>
 #include <SPI.h>
 #include <vector>
+#include <Preferences.h>
 #include "configuration.h"
 #include "credentials.h"
 
+// This file should not be in any publig git repos, it contains your secret APPKEY
+#include "../credentials-private.h"
+
 // -----------------------------------------------------------------------------
 // Globals
 // -----------------------------------------------------------------------------
@@ -42,6 +46,10 @@ const lmic_pinmap lmic_pins = {
     .dio = {DIO0_GPIO, DIO1_GPIO, DIO2_GPIO},
 };
 
+
+// Message counter, stored in RTC memory, survives deep sleep.
+static RTC_DATA_ATTR uint32_t count = 0;
+
 #ifdef USE_ABP
 // These callbacks are only used in over-the-air activation, so they are
 // left empty here (we cannot leave them out completely unless
@@ -53,7 +61,7 @@ void os_getDevKey (u1_t* buf) { }
 
 #ifdef USE_OTAA
 void os_getArtEui (u1_t* buf) { memcpy_P(buf, APPEUI, 8); }
-void os_getDevEui (u1_t* buf) { memcpy_P(buf, DEVEUI, 8); }
+void os_getDevEui (u1_t* buf) { memcpy(buf, DEVEUI, 8); }
 void os_getDevKey (u1_t* buf) { memcpy_P(buf, APPKEY, 16); }
 #endif
 
@@ -85,14 +93,100 @@ void forceTxSingleChannelDr() {
     ttn_sf(LORAWAN_SF);
 }
 
+
+// DevEUI generator using devices's MAC address - from https://github.com/cyberman54/ESP32-Paxcounter/blob/master/src/lorawan.cpp
+void gen_lora_deveui(uint8_t *pdeveui) {
+    uint8_t *p = pdeveui, dmac[6];
+    int i = 0;
+    esp_efuse_mac_get_default(dmac);
+    // deveui is LSB, we reverse it so TTN DEVEUI display
+    // will remain the same as MAC address
+    // MAC is 6 bytes, devEUI 8, set first 2 ones
+    // with an arbitrary value
+    *p++ = 0xFF;
+    *p++ = 0xFE;
+    // Then next 6 bytes are mac address reversed
+    for (i = 0; i < 6; i++) {
+        *p++ = dmac[5 - i];
+    }
+}
+
+
+static void printHex2(unsigned v) {
+    v &= 0xff;
+    if (v < 16)
+        Serial.print('0');
+    Serial.print(v, HEX);
+}
+
+// generate DevEUI from macaddr if needed
+void initDevEUI() {
+    bool needInit = true;
+    for(int i = 0; i < sizeof(DEVEUI); i++)
+        if(DEVEUI[i]) needInit = false;
+
+    if(needInit)
+        gen_lora_deveui(DEVEUI);
+
+    Serial.print("DevEUI: ");
+    for(int i = 0; i < sizeof(DEVEUI); i++) {
+        if (i != 0)
+                Serial.print("-");
+        printHex2(DEVEUI[i]);
+    }
+    Serial.println();
+}
+
 // LMIC library will call this method when an event is fired
 void onEvent(ev_t event) {
     switch(event) {
-    case EV_JOINED:
+    case EV_JOINED: {
         #ifdef SINGLE_CHANNEL_GATEWAY
         forceTxSingleChannelDr();
         #endif
-        break;
+
+        // Disable link check validation (automatically enabled
+        // during join, but because slow data rates change max TX
+        // size, we don't use it in this example.
+        if(!LORAWAN_ADR){
+            LMIC_setLinkCheckMode(0); // Link check problematic if not using ADR. Must be set after join
+        }
+
+        Serial.println(F("EV_JOINED"));
+
+        u4_t netid = 0;
+        devaddr_t devaddr = 0;
+        u1_t nwkKey[16];
+        u1_t artKey[16];
+        LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
+        Serial.print("netid: ");
+        Serial.println(netid, DEC);
+        Serial.print("devaddr: ");
+        Serial.println(devaddr, HEX);
+        Serial.print("AppSKey: ");
+        for (size_t i=0; i<sizeof(artKey); ++i) {
+            if (i != 0)
+                Serial.print("-");
+            printHex2(artKey[i]);
+        }
+        Serial.println("");
+        Serial.print("NwkSKey: ");
+        for (size_t i=0; i<sizeof(nwkKey); ++i) {
+            if (i != 0)
+                    Serial.print("-");
+            printHex2(nwkKey[i]);
+        }
+        Serial.println();
+
+        Preferences p;
+        if(p.begin("lora", false)) {
+            p.putUInt("netId", netid);
+            p.putUInt("devAddr", devaddr);
+            p.putBytes("nwkKey", nwkKey, sizeof(nwkKey));
+            p.putBytes("artKey", artKey, sizeof(artKey));
+            p.end();
+        }
+        break; }
     case EV_TXCOMPLETE:
         Serial.println(F("EV_TXCOMPLETE (inc. RX win. wait)"));
         if (LMIC.txrxFlags & TXRX_ACK) {
@@ -132,7 +226,22 @@ void ttn_response(uint8_t * buffer, size_t len) {
     }
 }
 
+// If the value for LORA packet counts is unknown, restore from flash
+static void initCount() {
+  if(count == 0) {
+    Preferences p;
+    if(p.begin("lora", true)) {
+        count = p.getUInt("count", 0);
+        p.end();
+    }
+  }
+}
+
+
 bool ttn_setup() {
+    initCount();
+    initDevEUI();
+
     // SPI interface
     SPI.begin(SCK_GPIO, MISO_GPIO, MOSI_GPIO, NSS_GPIO);
 
@@ -148,16 +257,6 @@ void ttn_join() {
     LMIC_setClockError(MAX_CLOCK_ERROR * CLOCK_ERROR / 100);
     #endif
 
-    #if defined(USE_ABP)
-
-        // Set static session parameters. Instead of dynamically establishing a session
-        // by joining the network, precomputed session parameters are be provided.
-        uint8_t appskey[sizeof(APPSKEY)];
-        uint8_t nwkskey[sizeof(NWKSKEY)];
-        memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
-        memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
-        LMIC_setSession(0x1, DEVADDR, nwkskey, appskey);
-
         #if defined(CFG_eu868)
 
             // Set up the channels used by the Things Network, which corresponds
@@ -184,6 +283,10 @@ void ttn_join() {
             // but only one group of 8 should (a subband) should be active
             // TTN recommends the second sub band, 1 in a zero based count.
             // https://github.com/TheThingsNetwork/gateway-conf/blob/master/US-global_conf.json
+            // in the US, with TTN, it saves join time if we start on subband 1
+            // (channels 8-15). This will get overridden after the join by
+            // parameters from the network. If working with other networks or in
+            // other regions, this will need to be changed.
             LMIC_selectSubBand(1);
 
         #elif defined(CFG_au915)
@@ -202,9 +305,6 @@ void ttn_join() {
         // Disable link check validation
         LMIC_setLinkCheckMode(0);
 
-        // TTN uses SF9 for its RX2 window.
-        LMIC.dn2Dr = DR_SF9;
-
         #ifdef SINGLE_CHANNEL_GATEWAY
         forceTxSingleChannelDr();
         #else
@@ -212,6 +312,19 @@ void ttn_join() {
         ttn_sf(LORAWAN_SF);
         #endif
 
+    #if defined(USE_ABP)
+
+        // Set static session parameters. Instead of dynamically establishing a session
+        // by joining the network, precomputed session parameters are be provided.
+        uint8_t appskey[sizeof(APPSKEY)];
+        uint8_t nwkskey[sizeof(NWKSKEY)];
+        memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
+        memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
+        LMIC_setSession(0x1, DEVADDR, nwkskey, appskey);
+
+        // TTN uses SF9 for its RX2 window.
+        LMIC.dn2Dr = DR_SF9;
+
         // Trigger a false joined
         _ttn_callback(EV_JOINED);
 
@@ -227,6 +340,30 @@ void ttn_join() {
         LMIC.txChnl = SINGLE_CHANNEL_GATEWAY;
         #endif
 
+        Preferences p;
+        p.begin("lora", true); // we intentionally ignore failure here
+        uint32_t netId = p.getUInt("netId", UINT32_MAX);
+        uint32_t devAddr = p.getUInt("devAddr", UINT32_MAX);
+        uint8_t nwkKey[16], artKey[16];
+        bool keysgood = p.getBytes("nwkKey", nwkKey, sizeof(nwkKey)) == sizeof(nwkKey) && 
+                        p.getBytes("artKey", artKey, sizeof(artKey)) == sizeof(artKey);
+        p.end(); // close our prefs
+
+        if(!keysgood) {
+            // We have not yet joined a network, start a full join attempt
+            // Make LMiC initialize the default channels, choose a channel, and
+            // schedule the OTAA join
+            Serial.println("No session saved, joining from scratch");
+            LMIC_startJoining();
+        }
+        else {
+            Serial.println("Rejoining saved session");
+            LMIC_setSession(netId, devAddr, nwkKey, artKey);
+
+            // Trigger a false joined
+            _ttn_callback(EV_JOINED);
+        }
+
     #endif
 }
 
@@ -239,11 +376,41 @@ void ttn_adr(bool enabled) {
     LMIC_setLinkCheckMode(!enabled);
 }
 
-void ttn_cnt(uint32_t num) {
+uint32_t ttn_get_count() {
-    LMIC_setSeqnoUp(num);
+  return count;
+}
+
+static void ttn_set_cnt() {
+    LMIC_setSeqnoUp(count);
+
+    // We occasionally mirror our count to flash, to ensure that if we lose power we will at least start with a count that is almost correct 
+    // (otherwise the TNN network will discard packets until count once again reaches the value they've seen).  We limit these writes to a max rate
+    // of one write every 5 minutes.  Which should let the FLASH last for 300 years (given the ESP32 NVS algoritm)
+    static uint32_t lastWriteMsec = UINT32_MAX; // Ensure we write at least once
+    uint32_t now = millis();
+    if(now < lastWriteMsec || (now - lastWriteMsec) > 5 * 60 * 1000L) { // write if we roll over (50 days) or 5 mins
+        lastWriteMsec = now;
+
+        Preferences p;
+        if(p.begin("lora", false)) {
+            p.putUInt("count", count);
+            p.end();
+        }
+    }
+}
+
+/// Blow away our prefs (i.e. to rejoin from scratch)
+void ttn_erase_prefs() {
+    Preferences p;
+    if(p.begin("lora", false)) {
+        p.clear();
+        p.end();
+    }
 }
 
 void ttn_send(uint8_t * data, uint8_t data_size, uint8_t port, bool confirmed){
+    ttn_set_cnt(); // we are about to send using the current packet count
+
     // Check if there is not a current TX/RX job running
     if (LMIC.opmode & OP_TXRXPEND) {
         _ttn_callback(EV_PENDING);
@@ -255,6 +422,7 @@ void ttn_send(uint8_t * data, uint8_t data_size, uint8_t port, bool confirmed){
     LMIC_setTxData2(port, data, data_size, confirmed ? 1 : 0);
 
     _ttn_callback(EV_QUEUED);
+    count++;
 }
 
 void ttn_loop() {

platformio.ini

@@ -0,0 +1,31 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[platformio]
+src_dir = main
+
+[env:esp32]
+platform = espressif32
+board = ttgo-t-beam
+framework = arduino
+
+; note: we add src to our include search path so that lmic_project_config can override
+build_flags = -Wall -Wextra -Wno-missing-field-initializers -O3 -Wl,-Map,.pio/build/esp32/output.map -D CFG_us915 -D CFG_sx1276_radio
+; -DLOG_LOCAL_LEVEL=ESP_LOG_DEBUG -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_DEBUG
+
+monitor_speed = 115200
+
+lib_deps =
+  https://github.com/mcci-catena/arduino-lmic
+  TinyGPSPlus
+  ESP8266_SSD1306
+  AXP202X_Library
+  SPI
+