Add PWM frequency & Duty Cycle offset

ziteh · Oct 5, 2021 · d1024bc · d1024bc
1 parent 451ad22
commit d1024bc
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Showing 2 changed files with 11 additions and 5 deletions.
diff --git a/lib/f103rb_pwm.cpp b/lib/f103rb_pwm.cpp
@@ -93,25 +93,28 @@ namespace F103RB
     TIM_Cmd(_Timer, DISABLE);              // The specified TIM peripheral
   }
 
-  void PWM::Set_Frequency(uint16_t frequency)
+  void PWM::Set_Frequency(uint16_t value)
   {
     /**
    *  TIM_Period = ((System_Frequency / TIM_Prescaler) / PWM_Frequency) - 1
    *
    *  The Maximum of System_Frequency is 72MHz (STM32F103RB)
    */
+    float frequency = value + this->FrequencyOffset;
 
     _TIM_TimeBaseStructure.TIM_Prescaler = 100;
     _TIM_TimeBaseStructure.TIM_Period = ((this->_RCC_Clocks.SYSCLK_Frequency / _TIM_TimeBaseStructure.TIM_Prescaler) / frequency) - 1;
 
     this->Init_Timer();
   }
 
-  void PWM::Set_DutyCycle(uint16_t dutyCycle)
+  void PWM::Set_DutyCycle(uint16_t value)
   {
-    if (_TIM_OCInitStructure.TIM_Pulse != this->ConvertDutyCycleToPulse(dutyCycle))
+    uint16_t targetDutyCycle = this->ConvertDutyCycleToPulse(value) + this->DutyCycleOffset;
+
+    if (_TIM_OCInitStructure.TIM_Pulse != targetDutyCycle)
     {
-      _TIM_OCInitStructure.TIM_Pulse = this->ConvertDutyCycleToPulse(dutyCycle);
+      _TIM_OCInitStructure.TIM_Pulse = targetDutyCycle;
       this->Init_Timer();
     }
   }

diff --git a/lib/f103rb_pwm.hpp b/lib/f103rb_pwm.hpp
@@ -36,6 +36,9 @@ namespace F103RB
     uint16_t ConvertDutyCycleToPulse(uint16_t dutyCycle);
 
   public:
+    float FrequencyOffset = 0.0;
+    float DutyCycleOffset = 0.0;
+
     PWM(GPIO_PortPinTypeDef portPin,
         TIM_TypeDef *Timer,
         PWM_TimerChannelTypeDef channel);
@@ -45,7 +48,7 @@ namespace F103RB
     void Disable(void);
 
     void Set_Frequency(uint16_t frequency);
-    void Set_DutyCycle(uint16_t dutyCycle);
+    void Set_DutyCycle(uint16_t value);
 
     uint16_t Get_Frequency(void);
     uint16_t Get_DutyCycle(void);