void TIM8_PWM_Init(u16 arr,u16 psc)

{  

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);  

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7  | GPIO_Pin_8 | GPIO_Pin_9;  

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; 

GPIO_Init(GPIOC, &GPIO_InitStructure);

TIM_TimeBaseStructure.TIM_Period = arr; 

TIM_TimeBaseStructure.TIM_Prescaler =psc; 

TIM_TimeBaseStructure.TIM_ClockDivision = 0; 

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 

TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure); 

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; 

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 

TIM_OCInitStructure.TIM_Pulse = 0; 

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 

TIM_OC1Init(TIM8, &TIM_OCInitStructure); 

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; 

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 

TIM_OCInitStructure.TIM_Pulse = 0; 

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 

TIM_OC2Init(TIM8, &TIM_OCInitStructure); 

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 

TIM_OCInitStructure.TIM_Pulse = 0; 

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 

TIM_OC3Init(TIM8, &TIM_OCInitStructure);  

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; 

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 

TIM_OCInitStructure.TIM_Pulse = 0; 

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; 

TIM_OC4Init(TIM8, &TIM_OCInitStructure);  

  TIM_CtrlPWMOutputs(TIM8,ENABLE);

TIM_OC1PreloadConfig(TIM8, TIM_OCPreload_Enable);  

TIM_OC2PreloadConfig(TIM8, TIM_OCPreload_Enable);  

TIM_OC3PreloadConfig(TIM8, TIM_OCPreload_Enable);  

TIM_OC4PreloadConfig(TIM8, TIM_OCPreload_Enable);  

TIM_ARRPreloadConfig(TIM8, ENABLE); 

TIM_Cmd(TIM8, ENABLE); 

}