diff --git a/radio/src/pulses/pulses.cpp b/radio/src/pulses/pulses.cpp
index 5c7fdc51e..7ac4a69e8 100755
--- a/radio/src/pulses/pulses.cpp
+++ b/radio/src/pulses/pulses.cpp
@@ -268,12 +268,12 @@ void enablePulsesExternalModule(uint8_t protocol)
 #if defined(PXX2) && defined(EXTMODULE_USART)
     case PROTOCOL_CHANNELS_PXX2_HIGHSPEED:
       extmoduleInvertedSerialStart(PXX2_HIGHSPEED_BAUDRATE);
-      mixerSchedulerSetPeriod(EXTERNAL_MODULE, PXX2_PERIOD);
+      mixerSchedulerSetPeriod(EXTERNAL_MODULE, PXX2_NO_HEARTBEAT_PERIOD);
       break;
 
     case PROTOCOL_CHANNELS_PXX2_LOWSPEED:
       extmoduleInvertedSerialStart(PXX2_LOWSPEED_BAUDRATE);
-      mixerSchedulerSetPeriod(EXTERNAL_MODULE, PXX2_PERIOD);
+      mixerSchedulerSetPeriod(EXTERNAL_MODULE, PXX2_NO_HEARTBEAT_PERIOD);
       break;
 #endif
 
@@ -347,7 +347,7 @@ bool setupPulsesExternalModule(uint8_t protocol)
     case PROTOCOL_CHANNELS_PXX2_LOWSPEED:
       extmodulePulsesData.pxx2.setupFrame(EXTERNAL_MODULE);
 #if defined(PCBSKY9X)
-      sheduleNextMixerCalculation(EXTERNAL_MODULE, PXX2_PERIOD);
+      sheduleNextMixerCalculation(EXTERNAL_MODULE, PXX2_NO_HEARTBEAT_PERIOD);
 #endif
       return true;
 #endif
@@ -487,9 +487,9 @@ static void enablePulsesInternalModule(uint8_t protocol)
 #if defined(INTMODULE_HEARTBEAT)
       // use backup trigger (1 ms later)
       init_intmodule_heartbeat();
-      mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_HEARTBEAT_PERIOD);
+      mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_MAX_HEARTBEAT_PERIOD);
 #else
-      mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_PERIOD);
+      mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_NO_HEARTBEAT_PERIOD);
 #endif
       break;
 #endif
@@ -547,9 +547,9 @@ bool setupPulsesInternalModule(uint8_t protocol)
       else {
 #if defined(INTMODULE_HEARTBEAT)
         mixerSchedulerResetTimer();
-        mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_HEARTBEAT_PERIOD);
+        mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_MAX_HEARTBEAT_PERIOD);
 #else
-        mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_PERIOD);
+        mixerSchedulerSetPeriod(INTERNAL_MODULE, PXX2_NO_HEARTBEAT_PERIOD);
 #endif
       }
       return result;
diff --git a/radio/src/pulses/pxx.h b/radio/src/pulses/pxx.h
index 8ea42b08e..90956fe35 100644
--- a/radio/src/pulses/pxx.h
+++ b/radio/src/pulses/pxx.h
@@ -29,8 +29,8 @@
 
 #define PXX2_LOWSPEED_BAUDRATE             230400
 #define PXX2_HIGHSPEED_BAUDRATE            450000
-#define PXX2_PERIOD                        4000/*us*/
-#define PXX2_HEARTBEAT_PERIOD              8000/*us 7ms frame rate + 1ms heartbeat backup*/
+#define PXX2_NO_HEARTBEAT_PERIOD           4000/*us*/
+#define PXX2_MAX_HEARTBEAT_PERIOD          (7000 + 1000)/*us 7ms frame rate + 1ms heartbeat backup*/
 #define PXX2_TOOLS_PERIOD                  1000/*us*/
 #define PXX2_FRAME_MAXLENGTH               64
 
diff --git a/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp b/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp
index a9ee219f2..68b2c47e5 100755
--- a/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp
@@ -141,7 +141,7 @@ void intmoduleSendBuffer(const uint8_t * data, uint8_t size)
 
 #if defined(INTMODULE_DMA_STREAM)
   if (!DMA_GetITStatus(INTMODULE_DMA_STREAM, INTMODULE_DMA_FLAG_TC))
-    return;;
+    return;
 
   DMA_InitTypeDef DMA_InitStructure;
   DMA_DeInit(INTMODULE_DMA_STREAM);