求大神，步進電機仿真的時候只轉到45度就停了

#include "motoSTEP.h"
#include "stm32f10x.h"
#define MOTO_PWM_GRP GPIOA
#define MOTO_PWM_PIN GPIO_Pin_8
#define MOTO_PWM_CLK RCC_APB2Periph_GPIOA
#define MOTO_DIR_GRP GPIOA
#define MOTO_DIR_PIN GPIO_Pin_13
void timer1PWM_Init(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
    TIM_OCInitTypeDef       TIM_OCInitStruct;
    GPIO_InitTypeDef GPIO_InitStruct;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | MOTO_PWM_CLK, ENABLE);
   /**MOTO CLK PIN**/
  GPIO_InitStruct.GPIO_Pin = MOTO_PWM_PIN;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(MOTO_PWM_GRP, &GPIO_InitStruct);
  
   /**MOTO DIR PIN**/
  GPIO_InitStruct.GPIO_Pin = MOTO_DIR_PIN;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(MOTO_DIR_GRP, &GPIO_InitStruct);
    TIM_TimeBaseInitStruct.TIM_Period = 10000; /*400Hz(2.5ms) */
    TIM_TimeBaseInitStruct.TIM_Prescaler = 4;
    TIM_TimeBaseInitStruct.TIM_ClockDivision = 0;
    TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseInitStruct);
    TIM_OCStructInit(&TIM_OCInitStruct);/*ÕâÒ»²½×îºÃ¼ÓÉÏ*/
   
    TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;//PWMģʽ1
    TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStruct.TIM_Pulse = 5000;//Âö¿íµ÷ÖÆ
    TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM1, &TIM_OCInitStruct);
    TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable);
    TIM_ARRPreloadConfig(TIM1, ENABLE);
    TIM_CtrlPWMOutputs(TIM1, ENABLE);/*ÕâÒ»¸öº¯ÊýÖ»Õë¶Ôtimer1ºÍtimer8*/
    TIM_Cmd(TIM1, ENABLE);      
}
void mdir(uint8_t dir)
{
if(dir==1)
  motoDIR=1;
else
  motoDIR=0;

}

你能知道，程序語句中每一句的含義么？它又出自何處？
不是你寫的當然不會知道，我也一樣。