Posted on May 17, 2011 at 14:30void PWMinit(void){
/* Time Base configuration */
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 7200;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);
/* Channel 1, 2,3 and 4 Configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM_OCInitStructure.TIM_Pulse = 200;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Set;
TIM_OC1Init(TIM8, &TIM_OCInitStructure);
TIM_OC2Init(TIM8, &TIM_OCInitStructure);
TIM_OC3Init(TIM8, &TIM_OCInitStructure);
TIM_CCPreloadControl(TIM8, DISABLE);
/* TIM1 counter enable */
TIM_Cmd(TIM8, ENABLE);
/* Main Output Enable */
TIM_CtrlPWMOutputs(TIM8, ENABLE);
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and in the main loop
TIM8->CCR1= 500;
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this code is working with my application
I looked at the supplied example code that uses the TIM3 timer and was able to change the TIM->CCR1 register inside a while loop in order to change the PWM duty cycle while the MCU is running. However, when I tried to do the same with TIM8, the duty cycle seems to stay constant at the initial TIM->CCR1 value that it was initialized with (duty cycle remains constant). Are there special conditions for TIM8 that I should be aware of when dealing with TIM8 specifically?
Any help would be greatly appreciated thanks!
