芯片是100个脚的 STM32F103VE ，实验TIM1_CH1 (PA8脚)的PWM，
程序烧录到芯片中，示波器一直测试不到A8脚的PWM信号，
但同一程序，在KEIL 4下仿真，却能看到正常的PWM信号； 占空比也是对的；
无语中......
以下是程序：
//PWM func ,use PA8 pin and TIM1 timer, 2012-10-23 16:53:33
u16 capture = 0;
u16 CCR2_Val = 0xFFFF/100*50 ; //占空比 50
/*
通过示波器察看PA.08的输出波形。
由于TIM1计数器的时钟频率为72MHz，希望各通道输出频率fTIM1为17.57KHz，
根据：fTIM1=TIM1CLK/(TIM1_Period + 1)，可得到TIM1预分频器的值TIM1_Period为0xFFFF。
根据公式：通道输出占空比 = TIM1_CCRx/(TIM1_Period + 1)，可以得到各通道比较/捕获寄存器的计数值。
*/
void PWM_Init(void)
{
TIM_TimeBaseInitTypeDef TIM1_TimeBaseStructure;
TIM_OCInitTypeDef TIM1_OCInitStructure;
TIM_BDTRInitTypeDef TIM1_BDTRInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOA Configuration: Channel 1 Output */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//时钟使能
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA , ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
/* TIM1 Peripheral Configuration */
TIM_DeInit(TIM1);
/* Time Base configuration */
TIM1_TimeBaseStructure.TIM_Prescaler = 0x0;
TIM1_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM1_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM1_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM1_TimeBaseStructure.TIM_RepetitionCounter = 0x0;
TIM_TimeBaseInit(TIM1,&TIM1_TimeBaseStructure);
/* Channel 1, 2,3 and 4 Configuration in PWM mode */
TIM1_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
TIM1_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM1_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM1_OCInitStructure.TIM_Pulse = CCR2_Val;
TIM1_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM1_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
TIM1_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM1_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
TIM_OC1Init(TIM1,&TIM1_OCInitStructure);
/* Automatic Output enable, Break, dead time and lock configuration*/
TIM1_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable;
TIM1_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable;
TIM1_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_1;
TIM1_BDTRInitStructure.TIM_DeadTime = 0x75;
TIM1_BDTRInitStructure.TIM_Break = TIM_Break_Enable;
TIM1_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_High;
TIM1_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable;
TIM_BDTRConfig(TIM1,&TIM1_BDTRInitStructure);
/* TIM1 counter enable */
TIM_Cmd(TIM1,ENABLE);
/* Main Output Enable */
TIM_CtrlPWMOutputs(TIM1,ENABLE);
} |
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