Minor refactoring.

include/time_manager.h

@@ -7,53 +7,54 @@
 
 typedef enum
 {
-    NTP_UPDATE_FAILED = 0,
-    NTP_UPDATE_OK = 1,
-    NTP_UPDATE_PENDING = 2,
-    NTP_UPDATE_RETRY_DELAY = 3,
-    NTP_UPDATE_TOO_EARLY = 4,
-    NTP_UPDATE_SETUP_FAILED = 5,
-} NtpUpdateState;
+    TIME_UPDATE_FAILED = 0,
+    TIME_UPDATE_OK = 1,
+    TIME_UPDATE_PENDING = 2,
+} TimeUpdateState;
 
 typedef enum
 {
     TM_INIT = 0,
     TM_INITIAL_SYNC = 1,
-    TM_RETRY_SYNC = 2,
-    TM_NORMAL = 3,
-    TM_PROLONGED_SYNC_FAIL = 4,
+    TM_NORMAL = 2,
+    TM_SYNC_OVERDUE = 3,
+    TM_SYNC_TIMEOUT = 4,
     TM_SETUP_FAILED = 5,
 } TimeManagerState;
 
 class TimeManager
 {
-#define NTP_MAX_UPDATE_TIME_US (500 * 1000) // 500ms max update time
+#define NTP_MAX_UPDATE_TIME_US (5 * 1000 * 1000) // 5000ms max update time
 
 public:
-    // constructor
+    // constructors
+    TimeManager();
     TimeManager(const char *tz,
                 const char *ntp_server,
-                uint32 ntp_update_period_s,
-                uint32 ntp_retry_delay_us,
+                bool (*is_wifi_connected)(void),
                 uint32 ntp_max_offline_time_s,
                 UDPLogger *logger);
 
-    // ntp methods
-    bool ntp_sync_successful(void) const;   // was there a NTP sync once?
-    bool ntp_update_failed_prolonged(void); // indicates if maximum time since last NTP update was too long
-    NtpUpdateState ntp_time_update();       // main NTP time update method, called in loop
+    // init
+    void init();
 
-    // ISR method
-    void increment_time_now_local(void); // should be called by timer ISR
+    // callback
+    void time_set_cb(void); // callback which is called when NTP time was set
+
+    // ntp methods
+    bool ntp_sync_successful(void) const; // was there a NTP sync once?
+    bool ntp_sync_overdue(void);          // function to check if NTP sync is overdue
+    bool ntp_sync_timeout(void);          // function to check if maximum time since last NTP sync has been reached
+    TimeUpdateState get_time();           // main time update method, called in loop
 
     // getter for time values
-    bool tm_isdst(void); // true if summertime
-    int tm_day(void);
-    int tm_hour(void);
-    int tm_min(void);
-    int tm_mon(void);
-    int tm_year(void);
-    struct tm time_info(void);
+    bool isdst(void) const; // true if summertime (daylight saving time)
+    int day(void) const;
+    int hour(void) const;
+    int minute(void) const;
+    int month(void) const;
+    int year(void) const;
+    struct tm time_info(void) const;
 
     // getter
     TimeManagerState tm_state(void) const; // get current state
@@ -63,26 +64,17 @@ public:
     void log_time(struct tm time_info) const; // log argument time_info
 
 private:
-    // setup methods
-    void _set_up_ntp(void);       // set up NTP server
-    void _set_up_timer_isr(void); // set up timer interrupt
+    void _set_up_ntp(void);           // set up NTP server
+    bool (*_is_wifi_connected)(void); // function to check if wifi is connected
 
+    const char *_ntp_server = "pool.ntp.org";           // ntp server address
     const char *_tz;                                    // timezone
-    const char *_ntp_server;                            // ntp server address
-    UDPLogger *_logger;                                 // logger instance
-    TimeManagerState _tm_state = TM_INIT;               // Main state
     struct tm _time_info = {0, 0, 0, 0, 0, 0, 0, 0, 0}; // structure tm holds time information
-    time_t _time_now_local = 0;                         // local timer value, updated by timer interrupt and synced by NTP when needed
-    time_t _time_now_ntp = 0;                           // NTP timer value, seconds since Epoch (1970) - UTC, only synced by NTP request.
+    time_t _now = 0;                                    // local time value
+    time_t _ntp_sync_timestamp_s = 0;                   // timestamp of last successful ntp sync
+    TimeManagerState _tm_state = TM_INIT;               // Main state
+    UDPLogger *_logger;                                 // logger instance
     uint32 _ntp_max_offline_time_s;                     // maximum time in seconds which is considered ok since last NTP update
-    uint32 _ntp_update_period_s;                        // NTP request update period in seconds
-    uint32 _ntp_retry_delay_us;                         // minimum retry delay in us between two NTP requests
-    uint32 _ntp_sync_timestamp_us = 0;                  // timestamp of last successful ntp update
 };
 
-inline void TimeManager::increment_time_now_local(void)
-{
-    _time_now_local++;
-}
-
 #endif /* TIME_MANAGER_H */

include/wordclock_constants.h

@@ -38,7 +38,7 @@
 #define PERIOD_HEARTBEAT_US (1 * 1000 * 1000)              // 1s
 #define PERIOD_MATRIX_UPDATE_US (100 * 1000)               // 100ms
 #define PERIOD_NIGHTMODE_CHECK_US (20 * 1000 * 1000)       // 20s
-#define PERIOD_TIME_UPDATE_US (500 * 1000)                 // 500ms
+#define PERIOD_TIME_UPDATE_US (1 * 1000 * 1000)            // 1000ms
 #define PERIOD_PONG_US (10 * 1000)                         // 10ms
 #define PERIOD_SNAKE_US (50 * 1000)                        // 50ms
 #define PERIOD_STATE_CHANGE_US (10 * 1000 * 1000)          // 10s
@@ -69,11 +69,9 @@
 #define MATRIX_HEIGHT (11)
 
 // NTP macros
-#define BUILD_YEAR (__DATE__ + 7)                  // Will expand to current year at compile time as string.
-#define NTP_MININUM_RX_YEAR (atoi(BUILD_YEAR) - 1) // Will expand to current year minus one at compile time.
-#define NTP_START_YEAR (1900)                      // NTP minimum year is 1900
-#define NTP_UPDATE_PERIOD_S (6 * 3600)             // 6h period between NTP updates
-#define NTP_RETRY_DELAY_US (10 * 1000 * 1000)      // 10s retry delay time between failed NTP requests
-#define NTP_MAX_OFFLINE_TIME_S (7 * 24 * 3600)     // Watchdog value, maxmimum offline time before a restart is triggered
+#define BUILD_YEAR (__DATE__ + 7)                   // Will expand to current year at compile time as string.
+#define NTP_MINIMUM_RX_YEAR (atoi(BUILD_YEAR) - 1)  // Will expand to current year minus one at compile time.
+#define NTP_START_YEAR (1900)                       // NTP minimum year is 1900
+#define NTP_MAX_OFFLINE_TIME_S (7 * 24 * 3600)      // Watchdog value, maximum offline time before a restart is triggered
 
 #endif /* WORDCLOCK_CONSTANTS_H */

include/wordclock_esp8266.h

@@ -82,7 +82,7 @@ void send_heartbeat(void);
 void set_dynamic_brightness(bool state);
 void set_main_color(uint8_t red, uint8_t green, uint8_t blue);
 void set_night_mode(bool on);
-void state_change(uint8_t newState);
+void state_change(ClockState_en new_state);
 void update_matrix(void);
 void write_settings_to_EEPROM(void);
 

platformio.ini

@@ -14,14 +14,12 @@ default_envs = nodemcuv2
 [env]
 platform = espressif8266
 board = nodemcuv2
-build_flags = -DUSING_TIM_DIV16=1
 framework = arduino
 lib_deps = 
 	adafruit/Adafruit BusIO@^1.15.0
 	adafruit/Adafruit NeoMatrix@^1.3.0
 	adafruit/Adafruit NeoPixel@^1.11.0
 	densaugeo/base64@^1.4.0
-	khoih-prog/ESP8266TimerInterrupt@^1.6.0
 	tzapu/WiFiManager@^0.16.0
 
 [env:nodemcuv2]

src/connectivity/time_manager.cpp

@@ -1,41 +1,76 @@
 #include "time_manager.h"
-#include <ESP8266TimerInterrupt.h> // https://github.com/khoih-prog/ESP8266TimerInterrupt
 #include "wordclock_constants.h"
-#include "time.h"
+#include <coredecls.h> // required for settimeofday_cb()
+#include <sntp.h>
+#include <time.h>
 
-extern UDPLogger logger;              // logging instance
-extern ESP8266Timer ITimer;           // ESP8266 Timer
-extern void IRAM_ATTR TimerHandler(); // ISR function
+extern UDPLogger logger; // logging instance
 
 // ----------------------------------------------------------------------------------
 //                                        Class
 // ----------------------------------------------------------------------------------
+TimeManager::TimeManager(){};
 TimeManager::TimeManager(const char *tz,
                          const char *ntp_server,
-                         uint32 ntp_update_period_s,
-                         uint32 ntp_retry_delay_us,
+                         bool (*is_wifi_connected)(void),
                          uint32 ntp_max_offline_time_s,
                          UDPLogger *logger)
 {
     _tz = tz;
     _ntp_server = ntp_server;
+    _is_wifi_connected = is_wifi_connected;
     _ntp_max_offline_time_s = ntp_max_offline_time_s;
-    _ntp_retry_delay_us = ntp_retry_delay_us;
-    _ntp_update_period_s = ntp_update_period_s;
     _logger = logger;
 }
 
+void TimeManager::init()
+{
+    // Set up NTP server once
+    _set_up_ntp();
+
+    if (_tm_state == TM_INITIAL_SYNC)
+    {
+        // force sntp reinit now
+        sntp_stop();
+        sntp_init();
+    }
+    settimeofday_cb([&]() { time_set_cb(); });
+}
+
 bool TimeManager::ntp_sync_successful(void) const
 {
-    return (_time_now_ntp > 0);
+    return (_now > 1716913300); // UTC timestamp in the past (28.05.2024)
 }
 
-bool TimeManager::ntp_update_failed_prolonged(void)
+bool TimeManager::ntp_sync_overdue(void)
 {
-    bool retval = false;
-    if (_time_now_local >= (_time_now_ntp + (time_t)_ntp_max_offline_time_s))
+    if (!ntp_sync_successful())
     {
-        _tm_state = TM_PROLONGED_SYNC_FAIL;
+        return false;
+    }
+
+    bool retval = false;
+    // after the ntp sync update delay has been reached six times, the sync is considered overdue
+    if (_now >= (_ntp_sync_timestamp_s + (time_t)(6 * (sntp_update_delay_MS_rfc_not_less_than_15000() / 1000))))
+    {
+        _tm_state = TM_SYNC_OVERDUE;
+        retval = true;
+    }
+    return retval;
+}
+
+bool TimeManager::ntp_sync_timeout(void)
+{
+    if (!ntp_sync_successful())
+    {
+        return false;
+    }
+
+    bool retval = false;
+    // after the maxmimum offline time has been reached, the sync is considered timed out
+    if (_now >= (_ntp_sync_timestamp_s + (time_t)_ntp_max_offline_time_s))
+    {
+        _tm_state = TM_SYNC_TIMEOUT;
         retval = true;
     }
     return retval;
@@ -46,117 +81,67 @@ bool TimeManager::ntp_update_failed_prolonged(void)
  *
  * @retval true if last update was successful
  */
-NtpUpdateState TimeManager::ntp_time_update()
+TimeUpdateState TimeManager::get_time()
 {
-    NtpUpdateState retval = NTP_UPDATE_PENDING; // NTP time update
-    struct tm time_info;                        // local NTP time info
-
-    // Set up NTP server once
-    if (_tm_state == TM_INIT)
-    {
-        _set_up_ntp();
-    }
-
-    if (_tm_state == TM_SETUP_FAILED)
-    {
-        return NTP_UPDATE_SETUP_FAILED;
-    }
-
-    // Check if minimum update delay has elapsed. This is always active to prevent too many NTP server requests!
-    if ((_tm_state != TM_INITIAL_SYNC) && (system_get_time() - _ntp_sync_timestamp_us) <= _ntp_retry_delay_us)
-    {
-        return NTP_UPDATE_RETRY_DELAY;
-    }
-
-    // Check if it is time for a NTP sync.
-    if ((_tm_state != TM_INITIAL_SYNC) && (_tm_state != TM_RETRY_SYNC) && (((system_get_time() - _ntp_sync_timestamp_us) / 1000000) <= _ntp_update_period_s))
-    {
-        return NTP_UPDATE_TOO_EARLY;
-    }
-
-    _ntp_sync_timestamp_us = system_get_time(); // NTP update start time
+    TimeUpdateState retval = TIME_UPDATE_PENDING; // NTP time update
+    uint32 timestamp_us = system_get_time();      // NTP update start time
+    struct tm time_info;                          // local NTP time info
 
     do
     {
-        time(&_time_now_ntp);                    // get time from server and save it into _time_now_ntp
-        localtime_r(&_time_now_ntp, &time_info); // convert time
-        yield();                                 // since this loop could take up to NTP_MAX_UPDATE_TIME_US
+        _now = time(nullptr);                 // update time
+        (void)localtime_r(&_now, &time_info); // convert time
+        yield();                              // since this loop could take up to NTP_MAX_UPDATE_TIME_US
 
-    } while (((system_get_time() - _ntp_sync_timestamp_us) <= NTP_MAX_UPDATE_TIME_US) && (time_info.tm_year < (NTP_MININUM_RX_YEAR - NTP_START_YEAR)));
+    } while (((system_get_time() - timestamp_us) <= NTP_MAX_UPDATE_TIME_US) && (time_info.tm_year < (NTP_MINIMUM_RX_YEAR - NTP_START_YEAR)));
 
-    retval = (time_info.tm_year <= (NTP_MININUM_RX_YEAR - NTP_START_YEAR)) ? NTP_UPDATE_FAILED : NTP_UPDATE_OK; // sanity check
+    retval = (time_info.tm_year <= (NTP_MINIMUM_RX_YEAR - NTP_START_YEAR)) ? TIME_UPDATE_FAILED : TIME_UPDATE_OK; // sanity check
 
-    if (retval == NTP_UPDATE_OK)
+    if (retval == TIME_UPDATE_OK)
     {
-        _ntp_sync_timestamp_us = system_get_time(); // save NTP update timestamp
-        _time_info = time_info;                     // take over time_info to member variable
-        log_time();                                 // log current time
-
-        if ((_tm_state != TM_INITIAL_SYNC) && (abs(_time_now_ntp - _time_now_local) > 10)) // in the case that the local time drifted more than 10s in _ntp_update_period_s
-        {
-            _logger->log_string(String("Difference between local and NTP time was more than 10 seconds!\n"));
-            _logger->log_string("Local time was: " + String(_time_now_local) + ", NTP time is: " + String(_time_now_ntp) + "\n");
-        }
-
-        _time_now_local = _time_now_ntp; // sync local time with NTP time
-
-        if (_tm_state == TM_INITIAL_SYNC) // only set up the timer once after NTP update was successful
-        {
-            _set_up_timer_isr();
-        }
-        else // set state to normal
-        {
-            _tm_state = TM_NORMAL;
-        }
+        _time_info = time_info; // take over time_info to member variable
+        _tm_state = TM_NORMAL;
     }
     else
     {
-        _tm_state = TM_RETRY_SYNC;
-        logger.log_string("NTP-Update was not successful. Retrying in " + String(_ntp_retry_delay_us / 1000) + "ms.");
+        logger.log_string("NTP-Update was not successful. Retrying in " + String(sntp_update_delay_MS_rfc_not_less_than_15000()) + "ms.");
     }
 
     return retval;
 }
 
-bool TimeManager::tm_isdst(void)
+bool TimeManager::isdst(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
-    return _time_info.tm_isdst > 0;
+    return (_time_info.tm_isdst > 0);
 }
 
-int TimeManager::tm_day(void)
+int TimeManager::day(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
-    return _time_info.tm_mday + 1;              // add 1 to get actual day
+    return (_time_info.tm_mday + 1); // add 1 to get actual day
 }
 
-int TimeManager::tm_hour(void)
+int TimeManager::hour(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
     return _time_info.tm_hour;
 }
 
-int TimeManager::tm_min(void)
+int TimeManager::minute(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
     return _time_info.tm_min;
 }
 
-int TimeManager::tm_mon(void)
+int TimeManager::month(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
-    return _time_info.tm_mon + 1;               // add 1 to get actual month
+    return (_time_info.tm_mon + 1); // add 1 to get actual month
 }
 
-int TimeManager::tm_year(void)
+int TimeManager::year(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
     return _time_info.tm_year + NTP_START_YEAR; // add start year to get actual year
 }
 
-struct tm TimeManager::time_info(void)
+struct tm TimeManager::time_info(void) const
 {
-    localtime_r(&_time_now_local, &_time_info); // convert time
     return _time_info;
 }
 
@@ -207,21 +192,23 @@ void TimeManager::_set_up_ntp(void)
     }
 }
 
-/**
- * @brief Sets up the timer ISR
- *
- */
-void TimeManager::_set_up_timer_isr(void)
+void TimeManager::time_set_cb(void)
 {
-    // set up timer interrupt after NTP update is done
-    if (ITimer.attachInterruptInterval(PERIOD_CLOCK_UPDATE_US, TimerHandler))
+    if ((*_is_wifi_connected)())
     {
-        _tm_state = TM_NORMAL;
-        logger.log_string(String("Timer ISR was attached successfully!"));
+        if (get_time() == TIME_UPDATE_OK)
+        {
+            _ntp_sync_timestamp_s = _now;
+            logger.log_string("NTP successfully synced at...");
+            log_time();
+        }
+        else
+        {
+            logger.log_string("NTP sync failed!");
+        }
     }
     else
     {
-        _tm_state = TM_SETUP_FAILED;
-        logger.log_string("WARNING: Timer interrupt was not attached!");
+        logger.log_string("NTP sync failed, WiFi is not connected!");
     }
 }

src/matrix/render_functions.cpp

@@ -179,58 +179,79 @@ String time_to_string(uint8_t hours, uint8_t minutes)
     // show hours
     switch (hours)
     {
-    case 0:
-        if (minutes >= 0 && minutes < 5)
+        case 0:
         {
-            message += "MITTERNACHT ";
+            if (minutes >= 0 && minutes < 5)
+            {
+                message += "MITTERNACHT ";
+            }
+            else
+            {
+                message += "ZWOLF ";
+            }
+            break;
         }
-        else
+        case 1:
+        {
+            message += "EIN";
+            message += (minutes > 4) ? "S " : " ";  // add "S" if needed
+            break;
+        }
+        case 2:
+        {
+            message += "ZWEI ";
+            break;
+        }
+        case 3:
+        {
+            message += "DREI ";
+            break;
+        }
+        case 4:
+        {
+            message += "VIER ";
+            break;
+        }
+        case 5:
+        {
+            message += "FUNF ";
+            break;
+        }
+        case 6:
+        {
+            message += "SECHS ";
+            break;
+        }
+        case 7:
+        {
+            message += "SIEBEN ";
+            break;
+        }
+        case 8:
+        {
+            message += "ACHT ";
+            break;
+        }
+        case 9:
+        {
+            message += "NEUN ";
+            break;
+        }
+        case 10:
+        {
+            message += "ZEHN ";
+            break;
+        }
+        case 11:
+        {
+            message += "ELF ";
+            break;
+        }
+        case 12:
         {
             message += "ZWOLF ";
+            break;
         }
-        break;
-    case 1:
-        message += "EIN";
-        // EIN(S)
-        if (minutes > 4)
-        {
-            message += "S";
-        }
-        message += " ";
-        break;
-    case 2:
-        message += "ZWEI ";
-        break;
-    case 3:
-        message += "DREI ";
-        break;
-    case 4:
-        message += "VIER ";
-        break;
-    case 5:
-        message += "FUNF ";
-        break;
-    case 6:
-        message += "SECHS ";
-        break;
-    case 7:
-        message += "SIEBEN ";
-        break;
-    case 8:
-        message += "ACHT ";
-        break;
-    case 9:
-        message += "NEUN ";
-        break;
-    case 10:
-        message += "ZEHN ";
-        break;
-    case 11:
-        message += "ELF ";
-        break;
-    case 12:
-        message += "ZWOLF ";
-        break;
     }
     if ((minutes < 5) && (hours != 0))
     {

src/wordclock_esp8266.cpp

@@ -28,8 +28,6 @@
 #include <Adafruit_NeoPixel.h>  // NeoPixel library used to run the NeoPixel LEDs: https://github.com/adafruit/Adafruit_NeoPixel
 #include <base64.hpp>
 #include <EEPROM.h>                // from ESP8266 Arduino Core (automatically installed when ESP8266 was installed via Boardmanager)
-#include <ESP8266_ISR_Timer.h>     // https://github.com/khoih-prog/ESP8266TimerInterrupt
-#include <ESP8266TimerInterrupt.h> // https://github.com/khoih-prog/ESP8266TimerInterrupt
 #include <ESP8266WebServer.h>
 #include <ESP8266WiFi.h>
 #include <WiFiManager.h> // https://github.com/tzapu/WiFiManager WiFi Configuration Magic
@@ -71,20 +69,16 @@ static Pong pong = Pong(&led_matrix, &logger);
 static Snake snake = Snake(&led_matrix, &logger);
 static Tetris tetris = Tetris(&led_matrix, &logger);
 
-// Time ManagerW
-static TimeManager tm_mgr = TimeManager(MY_TZ, NTP_SERVER_URL,
-                                        NTP_UPDATE_PERIOD_S,
-                                        NTP_RETRY_DELAY_US,
-                                        NTP_MAX_OFFLINE_TIME_S,
-                                        &logger);
+// Time Manager
+static TimeManager tm_mgr;
 
-// State variablesW
+// State variables
 static bool flg_night_mode = false;                     // State of nightmode
 static bool flg_reset_wifi_creds = false;               // Used to reset stored wifi credentials
 static float filter_factor = DEFAULT_SMOOTHING_FACTOR;  // Stores smoothing factor for led transition, value of 1 represents no smoothing.
 static uint32_t main_color_clock = colors_24bit[2];     // Color of the clock and digital clock
 static uint8_t current_brightness = DEFAULT_BRIGHTNESS; // Current brightness of LEDs
-static uint8_t current_state = (uint8_t)ST_CLOCK;       // Stores current state
+static ClockState_en current_state = ST_CLOCK; // Stores current state
 
 // Other variables
 static uint32 last_led_direct_us = 0;  // Time of last direct LED command (=> fall back to normal mode after timeout)
@@ -104,18 +98,6 @@ static const uint32_t period_timings[NUM_STATES] = {PERIOD_TIME_UPDATE_US, PERIO
                                                     PERIOD_ANIMATION_US, PERIOD_TETRIS_US, PERIOD_SNAKE_US,
                                                     PERIOD_PONG_US, PERIOD_ANIMATION_US};
 
-// ----------------------------------------------------------------------------------
-//                                   STATIC VARIABLES
-// ----------------------------------------------------------------------------------
-ESP8266Timer ITimer; // ESP8266 Timer
-
-// ----------------------------------------------------------------------------------
-//                                        ISR
-// ----------------------------------------------------------------------------------
-void IRAM_ATTR TimerHandler()
-{
-    tm_mgr.increment_time_now_local();
-}
 
 // ----------------------------------------------------------------------------------
 //                                        SETUP
@@ -153,7 +135,7 @@ void setup()
     led_matrix.set_current_limit(CURRENT_LIMIT_LED);
 
     // Turn on minutes LEDs (blue)
-    led_matrix.set_min_indicator(15, colors_24bit[6]);
+    led_matrix.set_min_indicator((uint8_t)0b1111, colors_24bit[6]);
     led_matrix.draw_on_matrix_instant();
 
     /* Use WiFiMaanger for handling initial Wifi setup */
@@ -172,7 +154,7 @@ void setup()
     WiFi.persistent(true);
 
     // Turn off minutes LEDs
-    led_matrix.set_min_indicator(15, 0);
+    led_matrix.set_min_indicator((uint8_t)0b1111, 0);
     led_matrix.draw_on_matrix_instant();
 
     // init ESP8266 File manager (LittleFS)
@@ -194,13 +176,16 @@ void setup()
         cold_start_setup();
     }
 
-    // get initial time
-    if (tm_mgr.ntp_time_update() == NTP_UPDATE_OK)
+    // set up time manager and get initial time
+    tm_mgr = TimeManager(MY_TZ, NTP_SERVER_URL, check_wifi_status, NTP_MAX_OFFLINE_TIME_S, &logger);
+    tm_mgr.init();
+
+    if (tm_mgr.get_time() == TIME_UPDATE_OK)
     {
         // show the current time for short time in words
-        String timeMessage = time_to_string(tm_mgr.tm_hour(), tm_mgr.tm_min());
+        String timeMessage = time_to_string(tm_mgr.hour(), tm_mgr.minute());
         show_string_on_clock(timeMessage, main_color_clock);
-        draw_minute_indicator(tm_mgr.tm_min(), main_color_clock);
+        draw_minute_indicator(tm_mgr.minute(), main_color_clock);
         led_matrix.draw_on_matrix_smooth(filter_factor);
     }
     else
@@ -209,11 +194,8 @@ void setup()
     }
 
     // init all animation modes
-    // init snake
     random_snake(true, 8, colors_24bit[1], -1);
-    // init spiral
     draw_spiral(true, spiral_direction, MATRIX_WIDTH - 6);
-    // init random tetris
     random_tetris(true);
 
     // Set range limits
@@ -280,17 +262,16 @@ void loop()
 
     if ((current_time_us - last_time_update_us) >= PERIOD_TIME_UPDATE_US)
     {
-        if (tm_mgr.ntp_time_update() == NTP_UPDATE_OK) // NTP time update
-        {
-            logger.log_string("NTP sync successful!");
-        }
+        (void)tm_mgr.get_time(); // NTP time update
 
-        if (tm_mgr.ntp_update_failed_prolonged() == true)
+        if (tm_mgr.ntp_sync_timeout())
         {
             logger.log_string("Trigger restart due to being offline for too long...");
             delay(100);
             ESP.restart();
         }
+
+       last_time_update_us = system_get_time();
     }
 
     if ((current_time_us - last_nightmode_check_us) >= PERIOD_NIGHTMODE_CHECK_US)
@@ -366,87 +347,87 @@ void handle_current_state()
 {
     switch (current_state)
     {
-    case ST_CLOCK: // state clock
-    {
-        if (tm_mgr.ntp_sync_successful() && tm_mgr.tm_state() == TM_NORMAL)
+        case ST_CLOCK: // state clock
         {
-            (void)show_string_on_clock(time_to_string((uint8_t)tm_mgr.tm_hour(), (uint8_t)tm_mgr.tm_min()), main_color_clock);
-            draw_minute_indicator((uint8_t)tm_mgr.tm_min(), main_color_clock);
+            if (tm_mgr.tm_state() == TM_NORMAL)
+            {
+                (void)show_string_on_clock(time_to_string((uint8_t)tm_mgr.hour(), (uint8_t)tm_mgr.minute()), main_color_clock);
+                draw_minute_indicator((uint8_t)tm_mgr.minute(), main_color_clock);
+            }
+            else if (tm_mgr.ntp_sync_overdue())  // if NTP sync is overdue
+            {
+                (void)show_string_on_clock(time_to_string((uint8_t)tm_mgr.hour(), (uint8_t)tm_mgr.minute()), main_color_clock);
+                draw_minute_indicator((uint8_t)tm_mgr.minute(), colors_24bit[6]); // in blue to indicate a network problem
+            }
+            else  // if no NTP sync has been done, only show 4 blue minute indicators
+            {
+                // clear matrix
+                led_matrix.flush();
+                // Turn on minutes LEDs (blue)
+                led_matrix.set_min_indicator((uint8_t)0b1111, colors_24bit[6]);
+                led_matrix.draw_on_matrix_instant();
+            }
+            break;
         }
-        else if (tm_mgr.ntp_sync_successful() && tm_mgr.tm_state() == TM_RETRY_SYNC)
+        case ST_DICLOCK: // state diclock
         {
-            (void)show_string_on_clock(time_to_string((uint8_t)tm_mgr.tm_hour(), (uint8_t)tm_mgr.tm_min()), main_color_clock);
-            draw_minute_indicator((uint8_t)tm_mgr.tm_min(), colors_24bit[6]); // in blue to indicate a network problem
+            if (tm_mgr.ntp_sync_successful())
+            {
+                show_digital_clock((uint8_t)tm_mgr.hour(), (uint8_t)tm_mgr.minute(), main_color_clock);
+            }
+            else
+            {
+                // clear matrix
+                led_matrix.flush();
+                // Turn on minutes LEDs (blue)
+                led_matrix.set_min_indicator((uint8_t)0b1111, colors_24bit[6]);
+                led_matrix.draw_on_matrix_instant();
+            }
+            break;
         }
-        else
+        case ST_SPIRAL: // state spiral
         {
-            // clear matrix
-            led_matrix.flush();
-            // Turn on minutes LEDs (blue)
-            led_matrix.set_min_indicator(15, colors_24bit[6]);
-            led_matrix.draw_on_matrix_instant();
+            int res = draw_spiral(false, spiral_direction, MATRIX_WIDTH - 2);
+            if ((bool)res && spiral_direction == 0)
+            {
+                // change spiral direction to closing (draw empty LEDs)
+                spiral_direction = true;
+                // init spiral with new spiral direction
+                draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
+            }
+            else if (res && spiral_direction == 1)
+            {
+                // reset spiral direction to normal drawing LEDs
+                spiral_direction = false;
+                // init spiral with new spiral direction
+                draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
+            }
+            break;
         }
-        break;
-    }
-    case ST_DICLOCK: // state diclock
-    {
-        if (tm_mgr.ntp_sync_successful())
+        case ST_TETRIS: // state tetris
         {
-            show_digital_clock((uint8_t)tm_mgr.tm_hour(), (uint8_t)tm_mgr.tm_min(), main_color_clock);
+            tetris.loopCycle();
+            break;
         }
-        else
+        case ST_SNAKE: // state snake
         {
-            // clear matrix
-            led_matrix.flush();
-            // Turn on minutes LEDs (blue)
-            led_matrix.set_min_indicator(15, colors_24bit[6]);
-            led_matrix.draw_on_matrix_instant();
+            snake.loopCycle();
+            break;
         }
-        break;
-    }
-    case ST_SPIRAL: // state spiral
-    {
-        int res = draw_spiral(false, spiral_direction, MATRIX_WIDTH - 2);
-        if ((bool)res && spiral_direction == 0)
+        case ST_PINGPONG: // state ping pong
         {
-            // change spiral direction to closing (draw empty LEDs)
-            spiral_direction = true;
-            // init spiral with new spiral direction
-            draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
+            pong.loopCycle();
+            break;
         }
-        else if (res && spiral_direction == 1)
+        case ST_HEARTS:
         {
-            // reset spiral direction to normal drawing LEDs
-            spiral_direction = false;
-            // init spiral with new spiral direction
-            draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
+            draw_heart_animation();
+            break;
+        }
+        default:
+        {
+            break;
         }
-        break;
-    }
-    case ST_TETRIS: // state tetris
-    {
-        tetris.loopCycle();
-        break;
-    }
-    case ST_SNAKE: // state snake
-    {
-        snake.loopCycle();
-        break;
-    }
-    case ST_PINGPONG: // state ping pong
-    {
-        pong.loopCycle();
-        break;
-    }
-    case ST_HEARTS:
-    {
-        draw_heart_animation();
-        break;
-    }
-    default:
-    {
-        break;
-    }
     }
 }
 
@@ -498,9 +479,9 @@ bool check_wifi_status()
  */
 void check_night_mode()
 {
-    // check if nightmode need to be activated
-    int hours = tm_mgr.tm_hour();
-    int minutes = tm_mgr.tm_min();
+    // Check if nightmode needs to be activated. This only toggles at the exact minute.
+    int hours = tm_mgr.hour();
+    int minutes = tm_mgr.minute();
 
     if ((hours == night_mode_times_ps->start_hour) && (minutes == night_mode_times_ps->start_min))
     {
@@ -522,43 +503,43 @@ void on_state_entry(uint8_t state)
     filter_factor = DEFAULT_SMOOTHING_FACTOR;
     switch (state)
     {
-    case ST_SPIRAL:
-    {
-        spiral_direction = 0; // Init spiral with normal drawing mode
-        draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
-        break;
-    }
-    case ST_TETRIS:
-    {
-        filter_factor = 1.0f; // no smoothing
-        tetris.ctrlStart();
-        break;
-    }
-    case ST_SNAKE:
-    {
-        filter_factor = 1.0f; // no smoothing
-        snake.initGame();
-        break;
-    }
-    case ST_PINGPONG:
-    {
-        filter_factor = 1.0f; // no smoothing
-        pong.initGame(1);
-        break;
-    }
-    default:
-    {
-        break;
-    }
+        case ST_SPIRAL:
+        {
+            spiral_direction = 0; // Init spiral with normal drawing mode
+            draw_spiral(true, spiral_direction, MATRIX_WIDTH - 1);
+            break;
+        }
+        case ST_TETRIS:
+        {
+            filter_factor = 1.0f; // no smoothing
+            tetris.ctrlStart();
+            break;
+        }
+        case ST_SNAKE:
+        {
+            filter_factor = 1.0f; // no smoothing
+            snake.initGame();
+            break;
+        }
+        case ST_PINGPONG:
+        {
+            filter_factor = 1.0f; // no smoothing
+            pong.initGame(1);
+            break;
+        }
+        default:
+        {
+            break;
+        }
     }
 }
 
 /**
- * @brief execute a state change to given newState
+ * @brief execute a state change to given new_state
  *
- * @param newState the new state to be changed to
+ * @param new_state the new state to be changed to
  */
-void state_change(uint8_t newState)
+void state_change(ClockState_en new_state)
 {
     if (flg_night_mode)
     {
@@ -566,9 +547,9 @@ void state_change(uint8_t newState)
     }
 
     led_matrix.flush();       // first clear matrix
-    current_state = newState; // set new state
-    on_state_entry(current_state);
-    logger.log_string("State change to: " + state_names[current_state]);
+    current_state = new_state; // set new state
+    on_state_entry((uint8_t)current_state);
+    logger.log_string("State change to: " + state_names[(uint8_t)current_state]);
     logger.log_string("FreeMemory=" + String(ESP.getFreeHeap()));
 }
 
@@ -660,7 +641,7 @@ void handle_button()
             }
             else
             {
-                state_change((current_state + 1) % (uint8_t)NUM_STATES);
+                state_change((ClockState_en)(((uint8_t)current_state + 1) % (uint8_t)NUM_STATES));
             }
         }
     }
@@ -735,6 +716,7 @@ void handle_command()
     {
         String mode_str = webserver.arg(0);
         logger.log_string("Mode change via Webserver to: " + mode_str);
+
         // set current mode/state accordant sent mode
         if (mode_str.equals("clock"))
         {
@@ -1049,9 +1031,9 @@ uint8_t update_brightness()
     {
         new_brightness = calculate_dynamic_brightness(brightness_ps->dyn_brightness_min,
                                                       brightness_ps->dyn_brightness_max,
-                                                      tm_mgr.tm_hour(),
-                                                      tm_mgr.tm_min(),
-                                                      tm_mgr.tm_isdst());
+                                                      tm_mgr.hour(),
+                                                      tm_mgr.minute(),
+                                                      tm_mgr.isdst());
     }
     else // use static brightness
     {