diff --git a/src/configmanager.cpp b/src/configmanager.cpp
index 419246ae..583377a8 100644
--- a/src/configmanager.cpp
+++ b/src/configmanager.cpp
@@ -19,7 +19,7 @@ void defaultConfig() {
   cfg.screenon = 1;           // 0=disabled, 1=enabled
   cfg.countermode = 0;        // 0=cyclic, 1=cumulative, 2=cyclic confirmed
   cfg.rssilimit = 0;          // threshold for rssilimiter, negative value!
-  cfg.sendcycle = SEND_CYCLE;  // payload send cycle [seconds/2]
+  cfg.sendcycle = SENDCYCLE;  // payload send cycle [seconds/2]
   cfg.wifichancycle =
       WIFI_CHANNEL_SWITCH_INTERVAL; // wifi channel switch cycle [seconds/100]
   cfg.blescantime =
diff --git a/src/main.cpp b/src/main.cpp
index 74094336..ff0d5e4b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -45,10 +45,8 @@ Tasks using i2c bus all must have same priority, because using mutex semaphore
 
 // ESP32 hardware timers
 -------------------------------------------------------------------------------
- 0	displayIRQ -> display refresh -> 40ms (DISPLAYREFRESH_MS in paxcounter.conf)
- 1  ppsIRQ -> pps clock irq -> 1sec
- 2	unused
- 3	unused
+ 0	displayIRQ -> display refresh -> 40ms (DISPLAYREFRESH_MS in
+paxcounter.conf) 1  ppsIRQ -> pps clock irq -> 1sec 2	unused 3	unused
 
 
 // Interrupt routines
@@ -316,15 +314,6 @@ void setup() {
   strcat_P(features, " OLED");
   DisplayState = cfg.screenon;
   init_display(PRODUCTNAME, PROGVERSION); // note: blocking call
-
-  // setup display refresh trigger IRQ using esp32 hardware timer
-  // https://techtutorialsx.com/2017/10/07/esp32-arduino-timer-interrupts/
-  // prescaler 80 -> divides 80 MHz CPU freq to 1 MHz, timer 0, count up
-  displayIRQ = timerBegin(0, 80, true);
-  // interrupt handler DisplayIRQ, triggered by edge
-  timerAttachInterrupt(displayIRQ, &DisplayIRQ, true);
-  // reload interrupt after each trigger of display refresh cycle
-  timerAlarmWrite(displayIRQ, DISPLAYREFRESH_MS * 1000, true);
 #endif
 
 // show payload encoder
@@ -395,16 +384,25 @@ void setup() {
   }
 #endif
 
+  // starting timers and interrupts
   assert(irqHandlerTask != NULL); // has interrupt handler task started?
-                                  // start timer triggered interrupts
   ESP_LOGI(TAG, "Starting Timers...");
+
+  // display interrupt
 #ifdef HAS_DISPLAY
+  // https://techtutorialsx.com/2017/10/07/esp32-arduino-timer-interrupts/
+  // prescaler 80 -> divides 80 MHz CPU freq to 1 MHz, timer 0, count up
+  displayIRQ = timerBegin(0, 80, true);
+  timerAttachInterrupt(displayIRQ, &DisplayIRQ, true);
+  timerAlarmWrite(displayIRQ, DISPLAYREFRESH_MS * 1000, true);
   timerAlarmEnable(displayIRQ);
 #endif
-  sendcycler.attach(SEND_CYCLE * 2, sendcycle);
+
+  // cyclic function interrupts
+  sendcycler.attach(SENDCYCLE * 2, sendcycle);
   housekeeper.attach(HOMECYCLE, housekeeping);
 
-// start button interrupt
+// button interrupt
 #ifdef HAS_BUTTON
 #ifdef BUTTON_PULLUP
   attachInterrupt(digitalPinToInterrupt(HAS_BUTTON), ButtonIRQ, RISING);
@@ -424,7 +422,7 @@ void setup() {
 
 #if defined HAS_IF482 || defined HAS_DCF77
 #ifndef TIME_SYNC_INTERVAL
-#error you must define TIME_SNYC_INTERVAL in paxcounter.conf
+#error for clock controller function TIME_SNYC_INTERVAL must be defined in paxcounter.conf
 #endif
   ESP_LOGI(TAG, "Starting Clock Controller...");
   clock_init();
diff --git a/src/paxcounter.conf b/src/paxcounter.conf
index a4efffeb..6d47a438 100644
--- a/src/paxcounter.conf
+++ b/src/paxcounter.conf
@@ -10,7 +10,7 @@
 #define VERBOSE                         1       // comment out to silence the device, for mute use build option
 
 // Payload send cycle and encoding
-#define SEND_CYCLE                      30      // payload send cycle [seconds/2], 0 .. 255
+#define SENDCYCLE                       30      // payload send cycle [seconds/2], 0 .. 255
 #define PAYLOAD_ENCODER                 2       // payload encoder: 1=Plain, 2=Packed, 3=Cayenne LPP dynamic, 4=Cayenne LPP packed
 
 // Set this to include BLE counting and vendor filter functions
diff --git a/src/payload.cpp b/src/payload.cpp
index ea3faf5d..45d7e6e3 100644
--- a/src/payload.cpp
+++ b/src/payload.cpp
@@ -457,7 +457,7 @@ void PayloadConvert::addButton(uint8_t value) {
 void PayloadConvert::addTime(time_t value) {
 #if (PAYLOAD_ENCODER == 4)
   uint32_t t = (uint32_t)value;
-  uint32_t tx_period = (uint32_t)SEND_CYCLE * 2;
+  uint32_t tx_period = (uint32_t)SENDCYCLE * 2;
   buffer[cursor++] = 0x03; // set config mask to UTCTime + TXPeriod
   // UTCTime in seconds
   buffer[cursor++] = (byte)((t & 0xFF000000) >> 24);