STM32 PWM控制步进电机的学习和问题

目的: 用STM32 的 TIM1 来产生PWM方波信号(占空比50%)，来控制步进电机运转，在通过更新TIM1的period 来改变电机的旋转速度，要求从0m/s到0.7m/s，在2S(秒)内完成加速过程。

下面是本人写的代码，不足之处是: 一开始不会进行加速，而是电机不动，过来有1分钟左右，然后电机从很慢的速度开始加速。 我不知道用什么命令来直接实现即时的频率更换。

代码如下：

PWM配置函数:

void Pwm_Configure(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM1_TimeBaseInitTypeDef TIM1_TimeBaseStructure;
TIM1_OCInitTypeDef TIM1_OCInitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

/* 使能PE端口时钟 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOE, ENABLE);
/* Enable TIM1 clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 , ENABLE);
/* 使能AFIO功能时钟 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
/* TIM1重映射 */
GPIO_PinRemapConfig(GPIO_FullRemap_TIM1, ENABLE);

/* Enable TIM2 clocks */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 , ENABLE);
/* TIM2重映射 */
GPIO_PinRemapConfig(GPIO_FullRemap_TIM2, ENABLE);

/* GPIOE Configuration: TIM1 Channel 3 and 4 Output 对应PWM0和PWM1*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13| GPIO_Pin_14 ;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOE, &GPIO_InitStructure);

/* GPIOB Configuration: TIM2 Channel 3 and 4 Output 对应PWM3和PWM4*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 ;//| GPIO_Pin_11 ;
GPIO_Init(GPIOB, &GPIO_InitStructure);

TIM1_DeInit();

/* Enable TIM1 clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 , ENABLE);

/* Time Base configuration */
TIM1_TimeBaseStructure.TIM1_Prescaler = 0x44A0; //72MHz/0xAF = Hz 0x15
TIM1_TimeBaseStructure.TIM1_CounterMode = TIM1_CounterMode_Up;
TIM1_TimeBaseStructure.TIM1_Period = 0xFFF; // KHz/4096（0xFFF+1）=100Hz
TIM1_TimeBaseStructure.TIM1_ClockDivision = 0x0;
TIM1_TimeBaseStructure.TIM1_RepetitionCounter = 0x0;

TIM1_TimeBaseInit(&TIM1_TimeBaseStructure);

/* TIM1 Channel 3 and 4 Configuration in PWM mode */

TIM1_OCInitStructure.TIM1_OCMode = TIM1_OCMode_PWM2;
TIM1_OCInitStructure.TIM1_OutputState = TIM1_OutputState_Enable;
TIM1_OCInitStructure.TIM1_Pulse = 0x7FF;
TIM1_OCInitStructure.TIM1_OCPolarity = TIM1_OCPolarity_Low;
TIM1_OCInitStructure.TIM1_OCIdleState = TIM1_OCIdleState_Set;

TIM1_OC3Init(&TIM1_OCInitStructure);
....

....

}

下面是main函数里面的死循环,变量的定义在这里省略了。

while(1)

{

u16 Prescale_value = (u16) 0x44A0 ; //对应PWM的输出频率的1Hz左右

if(Prescale_value > (u16) 0x15)

//0x15对应PWM输出的800多Hz对应电机速度约0.7m/s
{

Prescale_value = Prescale_value - (u16)0x05;
TIM1_PrescalerConfig(Prescale_value, TIM1_PSCReloadMode_Update);
TIM1_GenerateEvent(TIM1_EventSource_Update);
OSTimeDly(100);
GPIO_ResetBits(GPIOC, GPIO_Pin_8 | GPIO_Pin_9); //指示灯，观察程序是进入这里。
OSTimeDly(5);
}

}