STM32 PWM输出问题
请问有没有知道这个程序有什么问题吗，下载到芯片一直没有PWM输出，不知道为什么，请教一下，谢谢。。。。 找到问题所在了 ，少下面这一句，添加后就好了，不光要使能定时器、GPIO,还要使能功能复用RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); Period比Pulse小，就没有输出。 看你上面代码没有看到问题，你最好一步一步仿真看看到底怎么回事 官方例子看下
void TIM_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* TIM10 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM10, ENABLE);
/* GPIOF clock enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);
/* GPIOF Configuration: TIM10 CH1 (PF6) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 ;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;
GPIO_Init(GPIOF, &GPIO_InitStructure);
/* Connect TIM pins to AF3 */
GPIO_PinAFConfig(GPIOF, GPIO_PinSource6, GPIO_AF_TIM10);
}
int main(void)
{
/*!< At this stage the microcontroller clock setting is already configured,
this is done through SystemInit() function which is called from startup
file (startup_stm32f2xx.s) before to branch to application main.
To reconfigure the default setting of SystemInit() function, refer to
system_stm32f2xx.c file
*/
/* TIM Configuration */
TIM_Config();
/* ---------------------------------------------------------------------------
TIM10 Configuration: generate 1 PWM signal:
In this example TIM10 input clock (TIM10CLK) is set to 2 * APB2 clock (PCLK2),
since APB2 prescaler is different from 1.
TIM10CLK = 2 * PCLK2
PCLK2 = HCLK / 2
=> TIM10CLK = HCLK = SystemCoreClock
To get TIM10 counter clock at 20 MHz, the prescaler is computed as follows:
Prescaler = (TIM10CLK / TIM10 counter clock) - 1
Prescaler = (SystemCoreClock /20 MHz) - 1
To get TIM10 output clock at 30 KHz, the period (TIM10_ARR) is computed as follows:
ARR = (TIM10 counter clock / TIM10 output clock) - 1
= 665
TIM10 Channel1 duty cycle = (TIM10_CCR1/ TIM10_ARR)* 100 = 50%
Note:
SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f2xx.c file.
Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
function to update SystemCoreClock variable value. Otherwise, any configuration
based on this variable will be incorrect.
--------------------------------------------------------------------------- */
/* Compute the prescaler value */
PrescalerValue = (uint16_t) (SystemCoreClock / 20000000) - 1;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 665;
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM10, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init(TIM10, &TIM_OCInitStructure);
TIM_OC1PreloadConfig(TIM10, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM10, ENABLE);
/* TIM10 enable counter */
TIM_Cmd(TIM10, ENABLE);
while (1)
{}
} 从上面代码看不出PWM输出函数 本帖最后由 无薪税绵 于 2017-5-5 09:07 编辑
给你一个参考：
http://www.cnblogs.com/jiwangbujiu/p/5616376.html 本帖最后由 toofree 于 2017-5-5 09:50 编辑
问题暂未看出来。
IO模式后面设置过了，刚没看到
搞清楚实质. 脉宽 ,周期, 脉宽是通过match寄存器实现. 问题暂未看出来。 CCR1 = ??