diff --git a/radio/src/pulses/pulses.cpp b/radio/src/pulses/pulses.cpp
index 21c4d7eee..8579d0c42 100755
--- a/radio/src/pulses/pulses.cpp
+++ b/radio/src/pulses/pulses.cpp
@@ -317,7 +317,6 @@ static void enablePulsesInternalModule(uint8_t protocol)
     case PROTOCOL_CHANNELS_MULTIMODULE:
       intmodulePulsesData.multi.initFrame();
       intmoduleSerialStart(MULTIMODULE_BAUDRATE, true, USART_Parity_Even, USART_StopBits_2, USART_WordLength_9b);
-      intmoduleTimerStart(MULTIMODULE_PERIOD);
       break;
 #endif
     default:
diff --git a/radio/src/rtos.h b/radio/src/rtos.h
index 6e42ebf30..56de40825 100644
--- a/radio/src/rtos.h
+++ b/radio/src/rtos.h
@@ -230,6 +230,8 @@ template<int SIZE>
 
   #define RTOS_CREATE_FLAG(flag)        flag = CoCreateFlag(false, false)
   #define RTOS_SET_FLAG(flag)           (void)CoSetFlag(flag)
+  #define RTOS_CLEAR_FLAG(flag)         (void)CoClearFlag(flag)
+  #define RTOS_WAIT_FLAG(flag,timeout)  (void)CoWaitForSingleFlag(flag,timeout)
 
 #ifdef __cplusplus
   template<int SIZE>
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 e2f01f586..39efa3478 100755
--- a/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/intmodule_serial_driver.cpp
@@ -39,12 +39,6 @@ void intmoduleStop()
   USART_DeInit(INTMODULE_USART);
 
   GPIO_ResetBits(INTMODULE_GPIO, INTMODULE_TX_GPIO_PIN | INTMODULE_RX_GPIO_PIN);
-
-#if defined(INTERNAL_MODULE_MULTI)
-  // stop pulses timer
-  INTMODULE_TIMER->DIER &= ~TIM_DIER_CC2IE;
-  INTMODULE_TIMER->CR1 &= ~TIM_CR1_CEN;
-#endif
 }
 
 void intmodulePxx1SerialStart()
@@ -93,28 +87,6 @@ void intmoduleSerialStart(uint32_t baudrate, uint8_t rxEnable, uint16_t parity,
   }
 }
 
-#if defined(INTERNAL_MODULE_MULTI)
-void intmoduleTimerStart(uint32_t periodMs)
-{
-  // Timer
-  INTMODULE_TIMER->CR1 &= ~TIM_CR1_CEN;
-  INTMODULE_TIMER->PSC = INTMODULE_TIMER_FREQ / 2000000 - 1; // 0.5uS (2Mhz)
-  INTMODULE_TIMER->ARR = periodMs * 2000;
-  INTMODULE_TIMER->CCR2 = (periodMs - 1) * 2000;
-  INTMODULE_TIMER->CCER = TIM_CCER_CC3E;
-  INTMODULE_TIMER->CCMR2 = 0;
-  INTMODULE_TIMER->EGR = 1; // Restart
-
-  INTMODULE_TIMER->CCMR2 = TIM_CCMR2_OC3M_1 | TIM_CCMR2_OC3M_0; // Toggle CC1 o/p
-  INTMODULE_TIMER->SR &= ~TIM_SR_CC2IF; // Clear flag
-  INTMODULE_TIMER->DIER |= TIM_DIER_CC2IE;  // Enable this interrupt
-  INTMODULE_TIMER->CR1 |= TIM_CR1_CEN;
-
-  NVIC_EnableIRQ(INTMODULE_TIMER_IRQn);
-  NVIC_SetPriority(INTMODULE_TIMER_IRQn, 7);
-}
-#endif
-
 #define USART_FLAG_ERRORS (USART_FLAG_ORE | USART_FLAG_NE | USART_FLAG_FE | USART_FLAG_PE)
 extern "C" void INTMODULE_USART_IRQHandler(void)
 {
@@ -187,12 +159,3 @@ void intmoduleSendNextFrame()
 #endif
   }
 }
-
-#if defined(INTERNAL_MODULE_MULTI)
-extern "C" void INTMODULE_TIMER_IRQHandler()
-{
-  INTMODULE_TIMER->SR &= ~TIM_SR_CC2IF;           // clear flag
-  setupPulsesInternalModule();
-  intmoduleSendNextFrame();
-}
-#endif
diff --git a/radio/src/targets/horus/CMakeLists.txt b/radio/src/targets/horus/CMakeLists.txt
index ef9b75c42..6b25b8942 100644
--- a/radio/src/targets/horus/CMakeLists.txt
+++ b/radio/src/targets/horus/CMakeLists.txt
@@ -190,6 +190,7 @@ set(TARGET_SRC
   led_driver.cpp
   extmodule_driver.cpp
   trainer_driver.cpp
+  mixer_scheduler_driver.cpp
   ../common/arm/stm32/heartbeat_driver.cpp
   ../common/arm/stm32/timers_driver.cpp
   ../common/arm/stm32/intmodule_serial_driver.cpp
diff --git a/radio/src/targets/horus/board.cpp b/radio/src/targets/horus/board.cpp
index ac6e4e1f8..e026b3ad5 100644
--- a/radio/src/targets/horus/board.cpp
+++ b/radio/src/targets/horus/board.cpp
@@ -98,6 +98,7 @@ void boardInit()
                          AUDIO_RCC_APB1Periph |
                          INTMODULE_RCC_APB1Periph |
                          EXTMODULE_RCC_APB1Periph |
+                         MIXER_SCHEDULER_TIMER_RCC_APB1Periph |
                          GPS_RCC_APB1Periph |
                          BACKLIGHT_RCC_APB1Periph,
                          ENABLE);
diff --git a/radio/src/targets/horus/board.h b/radio/src/targets/horus/board.h
index c6cb49e87..e1772dd8b 100644
--- a/radio/src/targets/horus/board.h
+++ b/radio/src/targets/horus/board.h
@@ -174,9 +174,6 @@ void init_intmodule_heartbeat();
 void check_intmodule_heartbeat();
 
 void intmoduleSerialStart(uint32_t baudrate, uint8_t rxEnable, uint16_t parity, uint16_t stopBits, uint16_t wordLength);
-#if defined(INTERNAL_MODULE_MULTI)
-void intmoduleTimerStart(uint32_t periodMs);
-#endif
 void intmoduleSendByte(uint8_t byte);
 void intmoduleSendBuffer(const uint8_t * data, uint8_t size);
 void intmoduleSendNextFrame();
@@ -193,6 +190,14 @@ void stop_trainer_ppm();
 void init_trainer_capture();
 void stop_trainer_capture();
 
+// Mixer scheduler driver
+void mixerSchedulerInit();
+void mixerSchedulerStart(uint16_t periodUs);
+void mixerSchedulerStop();
+void mixerSchedulerWaitForTrigger(uint8_t timeoutMs);
+void mixerSchedulerEnableTrigger();
+void mixerSchedulerDisableTrigger();
+  
 // Keys driver
 enum EnumKeys
 {
diff --git a/radio/src/targets/horus/hal.h b/radio/src/targets/horus/hal.h
index 6f226d7b9..48bc922ac 100644
--- a/radio/src/targets/horus/hal.h
+++ b/radio/src/targets/horus/hal.h
@@ -365,7 +365,7 @@
 // Telemetry
 #define TELEMETRY_RCC_AHB1Periph        (RCC_AHB1Periph_GPIOD | RCC_AHB1Periph_DMA1)
 #define TELEMETRY_RCC_APB1Periph        RCC_APB1Periph_USART2
-#define TELEMETRY_RCC_APB2Periph        RCC_APB2Periph_TIM10
+#define TELEMETRY_RCC_APB2Periph        RCC_APB2Periph_TIM11
 #define TELEMETRY_DIR_GPIO              GPIOD
 #define TELEMETRY_DIR_GPIO_PIN          GPIO_Pin_4  // PD.04
 #define TELEMETRY_GPIO                  GPIOD
@@ -754,6 +754,13 @@
 #define TIMER_2MHz_RCC_APB1Periph       RCC_APB1Periph_TIM7
 #define TIMER_2MHz_TIMER                TIM7
 
+// Mixer scheduler timer
+#define MIXER_SCHEDULER_TIMER_RCC_APB1Periph RCC_APB1Periph_TIM13
+#define MIXER_SCHEDULER_TIMER                TIM13
+#define MIXER_SCHEDULER_TIMER_FREQ           (PERI1_FREQUENCY * TIMER_MULT_APB1)
+#define MIXER_SCHEDULER_TIMER_IRQn           TIM8_UP_TIM13_IRQn
+#define MIXER_SCHEDULER_TIMER_IRQHandler     TIM8_UP_TIM13_IRQHandler
+
 // Bluetooth
 #define STORAGE_BLUETOOTH
 #define BT_RCC_APB2Periph               RCC_APB2Periph_USART6
diff --git a/radio/src/targets/horus/mixer_scheduler_driver.cpp b/radio/src/targets/horus/mixer_scheduler_driver.cpp
new file mode 100644
index 000000000..548bfef97
--- /dev/null
+++ b/radio/src/targets/horus/mixer_scheduler_driver.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) OpenTX
+ *
+ * Based on code named
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "opentx.h"
+
+RTOS_FLAG_HANDLE mixerFlag;
+
+void mixerSchedulerInit()
+{
+    RTOS_CREATE_FLAG(mixerFlag);
+}
+
+void mixerSchedulerStart(uint16_t periodUs)
+{
+    MIXER_SCHEDULER_TIMER->CR1   = TIM_CR1_URS; // do not generate interrupt on soft update
+    MIXER_SCHEDULER_TIMER->PSC   = INTMODULE_TIMER_FREQ / 2000000 - 1; // 0.5uS (2Mhz)
+    MIXER_SCHEDULER_TIMER->CCER  = 0;
+    MIXER_SCHEDULER_TIMER->CCMR1 = 0;
+    MIXER_SCHEDULER_TIMER->ARR   = 2 * periodUs - 1;
+    MIXER_SCHEDULER_TIMER->EGR   = TIM_EGR_UG;   // reset timer
+
+    NVIC_EnableIRQ(MIXER_SCHEDULER_TIMER_IRQn);
+    NVIC_SetPriority(MIXER_SCHEDULER_TIMER_IRQn, 8);
+
+    MIXER_SCHEDULER_TIMER->SR   &= TIM_SR_UIF;   // clear interrupt flag
+    MIXER_SCHEDULER_TIMER->DIER |= TIM_DIER_UIE; // enable interrupt
+    MIXER_SCHEDULER_TIMER->CR1  |= TIM_CR1_CEN;
+}
+
+void mixerSchedulerStop()
+{
+    MIXER_SCHEDULER_TIMER->CR1 &= ~TIM_CR1_CEN;
+    NVIC_DisableIRQ(MIXER_SCHEDULER_TIMER_IRQn);
+}
+
+void mixerSchedulerEnableTrigger()
+{
+    MIXER_SCHEDULER_TIMER->DIER |= TIM_DIER_UIE; // enable interrupt
+}
+
+void mixerSchedulerDisableTrigger()
+{
+    MIXER_SCHEDULER_TIMER->DIER &= ~TIM_DIER_UIE; // disable interrupt
+}
+
+void mixerSchedulerWaitForTrigger(uint8_t timeoutMs)
+{
+    RTOS_CLEAR_FLAG(mixerFlag);
+    RTOS_WAIT_FLAG(mixerFlag, timeoutMs);
+}
+
+extern "C" void MIXER_SCHEDULER_TIMER_IRQHandler(void)
+{
+    MIXER_SCHEDULER_TIMER->SR &= ~TIM_SR_UIF; // clear flag
+    mixerSchedulerDisableTrigger();
+
+    // trigger mixer start
+    CoEnterISR();
+    CoSchedLock();
+    isr_SetFlag(mixerFlag);
+    CoSchedUnlock();
+    CoExitISR();
+}
diff --git a/radio/src/tasks.cpp b/radio/src/tasks.cpp
index 9cbe9e2bd..4f803e554 100644
--- a/radio/src/tasks.cpp
+++ b/radio/src/tasks.cpp
@@ -75,13 +75,21 @@ bool isForcePowerOffRequested()
 
 bool isModuleSynchronous(uint8_t module)
 {
-  uint8_t protocol = moduleState[module].protocol;
-  if (protocol == PROTOCOL_CHANNELS_PXX2_HIGHSPEED || protocol == PROTOCOL_CHANNELS_PXX2_LOWSPEED || protocol == PROTOCOL_CHANNELS_CROSSFIRE || protocol == PROTOCOL_CHANNELS_NONE)
-    return true;
-#if defined(INTMODULE_USART) || defined(EXTMODULE_USART)
-  if (protocol == PROTOCOL_CHANNELS_PXX1_SERIAL)
-    return true;
+  switch(moduleState[module].protocol) {
+
+    case PROTOCOL_CHANNELS_PXX2_HIGHSPEED:
+    case PROTOCOL_CHANNELS_PXX2_LOWSPEED:
+    case PROTOCOL_CHANNELS_CROSSFIRE:
+    case PROTOCOL_CHANNELS_NONE:
+
+#if defined(MULTIMODULE)
+    case PROTOCOL_CHANNELS_MULTIMODULE:
 #endif
+#if defined(INTMODULE_USART) || defined(EXTMODULE_USART)
+    case PROTOCOL_CHANNELS_PXX1_SERIAL:
+#endif
+      return true;
+  }
   return false;
 }
 
@@ -100,13 +108,17 @@ void sendSynchronousPulses()
   }
 }
 
+#define DEBUG_MIXER_SCHEDULER
+
 uint32_t nextMixerTime[NUM_MODULES];
 
 TASK_FUNCTION(mixerTask)
 {
-  static uint32_t lastRunTime;
   s_pulses_paused = true;
 
+  mixerSchedulerInit();
+  mixerSchedulerStart(6666); // 150 Hz
+
   while (true) {
 #if defined(PCBTARANIS) && defined(SBUS)
     // SBUS trainer
@@ -121,7 +133,22 @@ TASK_FUNCTION(mixerTask)
     bluetooth.wakeup();
 #endif
 
-    RTOS_WAIT_TICKS(1);
+    // TODO:
+    // - add trigger based on heartbeat driver
+    
+    // run mixer at least every 10ms
+    mixerSchedulerWaitForTrigger(10);
+
+#if defined(DEBUG_MIXER_SCHEDULER)
+    GPIO_SetBits(EXTMODULE_TX_GPIO, EXTMODULE_TX_GPIO_PIN);
+    GPIO_ResetBits(EXTMODULE_TX_GPIO, EXTMODULE_TX_GPIO_PIN);
+#endif
+
+    // TODO:
+    //  - compute next trigger
+
+    // re-enable trigger
+    mixerSchedulerEnableTrigger();
 
 #if defined(SIMU)
     if (pwrCheck() == e_power_off) {
@@ -133,36 +160,6 @@ TASK_FUNCTION(mixerTask)
     }
 #endif
 
-    uint32_t now = RTOS_GET_MS();
-    bool run = false;
-
-    if (now - lastRunTime >= 10) {
-      // run at least every 10ms
-      run = true;
-    }
-
-#if defined(INTMODULE_USART) && defined(INTMODULE_HEARTBEAT)
-    if ((moduleState[INTERNAL_MODULE].protocol == PROTOCOL_CHANNELS_PXX2_HIGHSPEED || moduleState[INTERNAL_MODULE].protocol == PROTOCOL_CHANNELS_PXX1_SERIAL) && heartbeatCapture.valid && heartbeatCapture.timestamp > lastRunTime) {
-      run = true;
-    }
-#endif
-
-    if (now == nextMixerTime[0]) {
-      run = true;
-    }
-
-#if NUM_MODULES >= 2
-    if (now == nextMixerTime[1]) {
-      run = true;
-    }
-#endif
-
-    if (!run) {
-      continue;  // go back to sleep
-    }
-
-    lastRunTime = now;
-
     if (!s_pulses_paused) {
       uint16_t t0 = getTmr2MHz();