#include "stm32f10x.h"

/** @addtogroup STM32F10x_StdPeriph_Examples

  * @{

  */

/** @addtogroup TIM_7PWM_Output

  * @{

  */

/* Private typedef -----------------------------------------------------------*/

/* Private define ------------------------------------------------------------*/

/* Private macro -------------------------------------------------------------*/

/* Private variables ---------------------------------------------------------*/

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;

TIM_OCInitTypeDef  TIM_OCInitStructure;

uint16_t TimerPeriod = 0;

uint16_t Channel1Pulse = 0, Channel2Pulse = 0, Channel3Pulse = 0, Channel4Pulse = 0;

/* Private function prototypes -----------------------------------------------*/

void RCC_Configuration(void);

void GPIO_Configuration(void);

/* Private functions ---------------------------------------------------------*/

/**

  * @brief   Main program

  * @param  None

  * @retval None

  */

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_stm32f10x_xx.s) before to branch to application main.

       To reconfigure the default setting of SystemInit() function, refer to

       system_stm32f10x.c file

     */    

  /* System Clocks Configuration */

  RCC_Configuration();

  /* GPIO Configuration */

  GPIO_Configuration();

  /* TIM1 Configuration ---------------------------------------------------

   Generate 7 PWM signals with 4 different duty cycles:

   TIM1CLK = SystemCoreClock, Prescaler = 0, TIM1 counter clock = SystemCoreClock

   SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density

   and Connectivity line devices and to 24 MHz for Low-Density Value line and

   Medium-Density Value line devices

   The objective is to generate 7 PWM signal at 17.57 KHz:

     - TIM1_Period = (SystemCoreClock / 17570) - 1

   The channel 1 and channel 1N duty cycle is set to 50%

   The channel 2 and channel 2N duty cycle is set to 37.5%

   The channel 3 and channel 3N duty cycle is set to 25%

   The channel 4 duty cycle is set to 12.5%

   The Timer pulse is calculated as follows:

     - ChannelxPulse = DutyCycle * (TIM1_Period - 1) / 100

  ----------------------------------------------------------------------- */

  /* Compute the value to be set in ARR regiter to generate signal frequency at 17.57 Khz */

  TimerPeriod = (SystemCoreClock / 17570 ) - 1;

  /* Compute CCR1 value to generate a duty cycle at 50% for channel 1 and 1N */

  Channel1Pulse = (uint16_t) (((uint32_t) 5 * (TimerPeriod - 1)) / 10);

  /* Compute CCR2 value to generate a duty cycle at 37.5%  for channel 2 and 2N */

  Channel2Pulse = (uint16_t) (((uint32_t) 375 * (TimerPeriod - 1)) / 1000);

  /* Compute CCR3 value to generate a duty cycle at 25%  for channel 3 and 3N */

  Channel3Pulse = (uint16_t) (((uint32_t) 25 * (TimerPeriod - 1)) / 100);

  /* Compute CCR4 value to generate a duty cycle at 12.5%  for channel 4 */

  Channel4Pulse = (uint16_t) (((uint32_t) 125 * (TimerPeriod- 1)) / 1000);

/*   计算周期 时间的方法 

  TIM_TimeBaseStructure.TIM_Prescaler = 0; //设置用来作为TIM 时钟频率除数的预分频值

  那么TIM时钟就为72M  1/72MHZ=0.01388...us    这就是 系统时间

  TimerPeriod = (SystemCoreClock / 17570 ) - 1;   //计算中断周期值

  (72MHz/17570) -1=4096.89..   中断周期值

   4096.89*0.01388=56.8US  这就是实际PWM中断周期时间 

   1/56.8US=17.6KHZ   1除以除以周期时间 就是频率 大约17.6KHz左右。

   各个 通道值计算结果。。

  Channel1Pulse = 5*（4096-1）/10 =2047       2047*0.01388=28.4US

  Channel2Pulse =  375 *(4096 - 1)) / 1000=1535  1535*0.01388=21.3US

  Channel3Pulse =  25 * (4096 - 1)) / 100=1023   1023*0.01388=14.19US

  Channel4Pulse =  125 *(4096 - 1)) / 1000=511   511*0.01388=7.09US

*/

  // //定时器初始化 函数  见库函数 P246页

  /* Time Base configuration */

  TIM_TimeBaseStructure.TIM_Prescaler = 0;  //设置用来作为TIM 时钟频率除数的预分频值

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数器模式  /* 向上计数模式 */

  TIM_TimeBaseStructure.TIM_Period = TimerPeriod; 

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;   //时钟分割  /* 采样分频 */

  TIM_TimeBaseStructure.TIM_RepetitionCounter = 0; //设置 周期 计数值

  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  //TIM1 配置  见 库函数 P294 页

  /* Channel 1, 2,3 and 4 Configuration in PWM mode */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;    //脉冲宽度调制模式2

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;  //使能输出比较状态

  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable; //使能  互补 输出状态

  TIM_OCInitStructure.TIM_Pulse = Channel1Pulse;  //脉冲 值

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出比较极性低

  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;//互补 输出极性高

  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;   //MOE=0 设置 TIM1输出比较空闲状态

  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;//MOE=0 重置 TIM1输出比较空闲状态

  TIM_OC1Init(TIM1, &TIM_OCInitStructure); //设定好的参数 初始化TIM 

  TIM_OCInitStructure.TIM_Pulse = Channel2Pulse; //脉宽值

  TIM_OC2Init(TIM1, &TIM_OCInitStructure); //设定好的参数 初始化TIM 

  TIM_OCInitStructure.TIM_Pulse = Channel3Pulse; //脉宽值

  TIM_OC3Init(TIM1, &TIM_OCInitStructure); //设定好的参数 初始化TIM 

  TIM_OCInitStructure.TIM_Pulse = Channel4Pulse; //脉宽值

  TIM_OC4Init(TIM1, &TIM_OCInitStructure);//设定好的参数 初始化TIM 

  /* TIM1 counter enable */

  TIM_Cmd(TIM1, ENABLE); //使能 TIM1

  /* TIM1 Main Output Enable */

  TIM_CtrlPWMOutputs(TIM1, ENABLE);    //使能 TIM1 输出

  while (1)

  {}

}

/**

  * @brief  Configures the different system clocks.

  * @param  None

  * @retval None

  */

void RCC_Configuration(void)

{

  /* TIM1, GPIOA, GPIOB, GPIOE and AFIO clocks enable */

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOE|

                         RCC_APB2Periph_GPIOB |RCC_APB2Periph_AFIO, ENABLE);

}

/**

  * @brief  Configure the TIM1 Pins.

  * @param  None

  * @retval None

  */

void GPIO_Configuration(void)

{

  GPIO_InitTypeDef GPIO_InitStructure;

#ifdef STM32F10X_CL

  /* GPIOE Configuration: Channel 1/1N, 2/2N, 3/3N and 4 as alternate function push-pull */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9|GPIO_Pin_11|GPIO_Pin_13|GPIO_Pin_14|

                                GPIO_Pin_8|GPIO_Pin_10|GPIO_Pin_12;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOE, &GPIO_InitStructure);

  /* TIM1 Full remapping pins */

  GPIO_PinRemapConfig(GPIO_FullRemap_TIM1, ENABLE);

#else

  /* GPIOA Configuration: Channel 1, 2 and 3 as alternate function push-pull */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 | GPIO_Pin_11;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* GPIOB Configuration: Channel 1N, 2N and 3N as alternate function push-pull */

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;

  GPIO_Init(GPIOB, &GPIO_InitStructure);

#endif

}

#ifdef  USE_FULL_ASSERT

/**

  * @brief  Reports the name of the source file and the source line number

  *         where the assert_param error has occurred.

  * @param  file: pointer to the source file name

  * @param  line: assert_param error line source number

  * @retval None

  */

void assert_failed(uint8_t* file, uint32_t line)

{

  /* User can add his own implementation to report the file name and line number,

     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  while (1)

  {}

}

#endif

/**

  * @}

  */

/**

  * @}

  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/