diff --git a/cores/arduino/wiring_analog.c b/cores/arduino/wiring_analog.c
index 1dc6775..c497b6b 100644
--- a/cores/arduino/wiring_analog.c
+++ b/cores/arduino/wiring_analog.c
@@ -104,9 +104,23 @@ It is recommended to enable the timer in the following order:
 */
 void analogWrite(uint32_t PinNumber, uint32_t writeVal)
 {
-  if (digitalPinHasPWM(PinNumber))
+  if (writeVal > WriteValMax)   writeVal = WriteValMax;
+
+  if (digitalPinPwmIsOn(PinNumber) > 0)      // pin has pwm and pwm is already on
   {
-    if (writeVal > WriteValMax)   writeVal = WriteValMax;
+    // we can only change writeVal if it is differ from current value
+    TIMER32_TypeDef* timer = pwmPinToTimer(PinNumber);
+    uint32_t newOCR = (uint32_t) (((uint64_t)pwmTopVal * writeVal) / WriteValMax); 
+    if (timer->CHANNELS[pwmPinToTimerChannel(PinNumber)].OCR != newOCR)
+    {
+      //  if new ocr differs from current, set new ocr
+      timer->CHANNELS[pwmPinToTimerChannel(PinNumber)].OCR = newOCR;
+    }
+  }
+  else if (digitalPinPwmIsOn(PinNumber) == 0) // pin has pwm and pwm is off
+  {
+    // init pin as pwm
+    uint32_t OCRval = (uint32_t) (((uint64_t)pwmTopVal * writeVal) / WriteValMax);
 
     // initialization of the required timer
     htimer32.Instance         = pwmPinToTimer(PinNumber);
@@ -127,7 +141,7 @@ void analogWrite(uint32_t PinNumber, uint32_t writeVal)
     htimer32_channel.PWM_Invert     = TIMER32_CHANNEL_NON_INVERTED_PWM;
     htimer32_channel.Mode           = TIMER32_CHANNEL_MODE_PWM;
     htimer32_channel.CaptureEdge    = TIMER32_CHANNEL_CAPTUREEDGE_RISING;
-    htimer32_channel.OCR            = (uint32_t) (((uint64_t)pwmTopVal * writeVal) / WriteValMax);
+    htimer32_channel.OCR            = OCRval;
     htimer32_channel.Noise          = TIMER32_CHANNEL_FILTER_OFF;
     HAL_Timer32_Channel_Init(&htimer32_channel);
 
@@ -137,7 +151,7 @@ void analogWrite(uint32_t PinNumber, uint32_t writeVal)
     HAL_Timer32_Start(&htimer32);
     pwmIsInited++; // increase inited channels qty
   }
-  else
+  else  // pin doesn't have pwm
     ErrorMsgHandler("analogWrite(): invalid pwm pin number");
 }
 
@@ -168,14 +182,17 @@ It is recommended to turn off the timer in the following order:
 - Write 0 to the INT_CLEAR register;
 - Set TIM_EN to 0.
 */
+// use only if digitalPinPwmIsOn(PinNumber) > 0
 void analogWriteStop(uint32_t PinNumber)
 {
-  if (digitalPinHasPWM(PinNumber) && (pwmIsInited > 0) && digitalPinPwmIsOn(PinNumber))
+  if ((pwmIsInited > 0))
   {
     // load the timer address and channel number corresponding to the specified pin
     htimer32.Instance               = pwmPinToTimer(PinNumber);
-    htimer32_channel.TimerInstance  = htimer32.Instance;
     htimer32_channel.ChannelIndex   = pwmPinToTimerChannel(PinNumber);
+    htimer32.Instance->CHANNELS[htimer32_channel.ChannelIndex].OCR = 0;
+    htimer32_channel.TimerInstance  = htimer32.Instance;
+
     // deinit channel
     HAL_Timer32_Channel_DeInit(&htimer32_channel);
     pwmIsInited--; // decrease inited channels qty