第一次发贴，不知道要悬赏分数，导致直接结贴，现在重发，不知道违反规则没有。
void TIM2_NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/*
* 函数名：TIM2_GPIO_Config
* 描述 ：配置TIM2复用输出PWM时用到的I/O
* 输入 ：无
* 输出 ：无
* 调用 ：内部调用
*/
static void TIM2_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOB clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
/*GPIOA Configuration: TIM2 channel 1 and 2 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // 推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}
/*
* 函数名：TIM2_Mode_Config
* 描述 ：配置TIM3输出的PWM信号的模式，如周期、极性、占空比
* 输入 ：无
* 输出 ：无
* 调用 ：内部调用
*/
static void TIM2_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
/* TIM2 clock enable */
//PCLK1经过2倍频后作为TIM2的时钟源等于72MHz
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 , ENABLE);
TIM2_NVIC_Configuration();
TIM_DeInit(TIM2);
TIM_TimeBaseStructure.TIM_Period = (1); /* 自动重装载寄存器周期的值(计数值) */
/* 累计 TIM_Period个频率后产生一个更新或者中断 */
TIM_TimeBaseStructure.TIM_Prescaler = (1); /* 时钟预分频数 72M/1== 72MHZ */
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; /* 采样分频 */
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; /* 向上计数模式 */
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
// TIM_ClearFlag(TIM2, TIM_FLAG_Update); /* 清除溢出中断标志 */
TIM_Cmd(TIM2, ENABLE); /* 开启时钟 */
}
中断里面引脚输出电压翻转
void TIM2_IRQHandler(void)
{
if ( TIM_GetITStatus(TIM2 , TIM_IT_Update) != RESET )
{
TIM_ClearITPendingBit(TIM2 , TIM_FLAG_Update);
if(i++)
{
i = 0;
GPIO_ResetBits(GPIOB,GPIO_Pin_5);
}
else
{
GPIO_SetBits(GPIOB, GPIO_Pin_5);
}
}
}
如果用PWM频率最高只有72KHz，因为要保证1%的占空比，所以72M/100=720KHZ，但没有用PWM，直接控制引脚，频率应该更快才对，怎么只有280K，最多288K，频率是在示波器上看到的，实测PWM最高只能
到72KHZ,这又是怎么回事？
static void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* PWM信号电平跳变值 */
u16 CCR1_Val = 500;
u16 CCR2_Val = 500;
u16 CCR3_Val = 500;
u16 CCR4_Val = 500;
// u16 CR1_Val = 500;
// u16 CCR2_Val = 375;
// u16 CCR3_Val = 250;
// u16 CCR4_Val = 125;
/* -----------------------------------------------------------------------
TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
TIM3CLK = 72 MHz, Prescaler = 0x0, TIM3 counter clock = 72 MHz
TIM3 ARR Register = 999 => TIM3 Frequency = TIM3 counter clock/(ARR + 1)
TIM3 Frequency = 72 KHz.
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
----------------------------------------------------------------------- */
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = (1000); // 当定时器从0计数到999，即为1000次，为一个定时周期
TIM_TimeBaseStructure.TIM_Prescaler = 0; // 设置预分频：不预分频，即为72MHz
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ; // 设置时钟分频系数：不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Down; // 向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; // 配置为PWM模式1
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR1_Val; // 设置跳变值，当计数器计数到这个值时，电平发生跳变
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; // 当定时器计数值小于CCR1_Val时为高电平
TIM_OC1Init(TIM3, &TIM_OCInitStructure); // 使能通道1
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val; // 设置通道2的电平跳变值，输出另外一个占空比的PWM
TIM_OC2Init(TIM3, &TIM_OCInitStructure); // 使能通道2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val; // 设置通道3的电平跳变值，输出另外一个占空比的PWM
TIM_OC3Init(TIM3, &TIM_OCInitStructure); // 使能通道3
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val; // 设置通道4的电平跳变值，输出另外一个占空比的PWM
TIM_OC4Init(TIM3, &TIM_OCInitStructure); // 使能通道4
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE); // 使能TIM3重载寄存器ARR
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE); // 使能定时器3
}
真有些晕了，新手，请高手指教 |
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