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- 2014-9-16
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5金钱
如题，程序里有两个功能，一是定时器1输出两路PWM，单独仿真和下载进去没有问题，都有输出；
二是通过定时器2周期性中断改变定时器1的脉宽，实现脉宽调节功能，加上这个功能后，仿真可以实现，下载后没输出
什么原因呢？
void TIM1_PWM_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
// NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); //使能定时器3时钟
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8|GPIO_Pin_9; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIO
GPIO_ResetBits(GPIOA,GPIO_Pin_8|GPIO_Pin_9);
//初始化TIM1
TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_CenterAligned3; //TIM向上计数模式
// TIM_TimeBaseStructure.TIM_RepetitionCounter = 10;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
TIM_OC1Init(TIM1, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM3 OC2
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //选择定时器模式:TIM脉冲宽度调制模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
TIM_OC2Init(TIM1, &TIM_OCInitStructure);
// TIM_ClearFlag(TIM1, TIM_FLAG_Update); //清中断，以免一启用中断后立即产生中断
// TIM_CtrlPWMOutputs(TIM1,ENABLE);
// TIM_Cmd(TIM1, ENABLE); //使能TIM3
}
void TIM3_Int_Init(u16 arr,u16 psc)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //时钟使能
TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 计数到5000为500ms
TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 10Khz的计数频率
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //使能指定的TIM3中断,允许更新中断
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn; //TIM3中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //先占优先级0级
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3; //从优先级3级
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能
NVIC_Init(&NVIC_InitStructure); //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器
TIM_Cmd(TIM3, ENABLE); //使能TIMx外设
}
extern u16 Pulse1,Pulse2;
extern u16  ulse_Add; // 5%
//定时器3中断服务程序
void TIM3_IRQHandler(void) //TIM3中断
{
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //检查指定的TIM中断发生与否:TIM 中断源
{
TIM_ClearITPendingBit(TIM3, TIM_IT_Update ); //清除TIMx的中断待处理位:TIM 中断源
if(Pulse_Add==0)
{ TIM_SetCompare1(TIM1,500);
TIM_SetCompare2(TIM1,500);
}
else
{Pulse_Add=Pulse_Add-25;
Pulse1=500+Pulse_Add;
Pulse2=500-Pulse_Add;
TIM_SetCompare1(TIM1,Pulse1);
TIM_SetCompare2(TIM1,Pulse2);
}
}
// TIM_CtrlPWMOutputs(TIM1,ENABLE);
// TIM_Cmd(TIM1, ENABLE); //使能TIM3
}
int main(void)
{
// u16 led0pwmval=0;
// u8 dir=1;
delay_init(); //延时函数初始化
NVIC_Configuration(); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
// uart_init(9600); //串口初始化为9600
// LED_Init(); //LED端口初始化
// TIM3_PWM_Init(899,0); //不分频。PWM频率=72000/900=8Khz
TIM3_Int_Init(999,7199);
TIM1_PWM_Init(999,0); //预分频9，PWM频率=72000000/1000=72khz 定时器输出频率的计算公式：f(OC1) = 72,000,000 / (ARR - 1)*(PSC - 1);
TIM_SetCompare1(TIM1,500+475);
TIM_SetCompare2(TIM1,500-475);
TIM_CtrlPWMOutputs(TIM1,ENABLE);
TIM_Cmd(TIM1, ENABLE);
TIM_Cmd(TIM3, ENABLE);
while(1)
{ }
}
下载进板子就没输出，为什么呢？可以确定管脚没问题，因为单独不变占空比可以有输出的
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发表于 2014-11-20 10:36:33
发表于 2014-11-20 10:36:34
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