STM8L探索套件学习笔记-综合应用（十八）

今天使用到的外设比较多，有DMA,TIM1,ADC。使用ADC1的通道24即PF1采集电位器的电压，由DMA1的通道0传输到Buffer。同时由DMA1的通道2将Buffer传输到TIM1外设上，也就是TIM1_CCR1H寄存器，能够改变PWM波的占空比。我们将PWM输出端连接到板上LED3上，这样就实现了用电位器调节LED3的亮度的作用。我们转了这么大弯，但能够学到很多，下面是代码：
void main(void)
{
  //1使能时钟
  /* Enable ADC1 clock */
  CLK_PeripheralClockConfig(CLK_Peripheral_ADC1, ENABLE);
 
  /* Enable TIM1 clock */
  CLK_PeripheralClockConfig(CLK_Peripheral_TIM1, ENABLE);
 
  /* Enable DMA1 clock */
  CLK_PeripheralClockConfig(CLK_Peripheral_DMA1, ENABLE);
  //2设置ADC
  /* Initialise and configure ADC1 */
  ADC_Init(ADC1, ADC_ConversionMode_Continuous, ADC_Resolution_12Bit, ADC_Prescaler_2);
  ADC_SamplingTimeConfig(ADC1, ADC_Group_SlowChannels, ADC_SamplingTime_384Cycles);
 
  /* Enable ADC1 */
  ADC_Cmd(ADC1, ENABLE);
 
  /* Enable ADC1 Channels 24 */
  ADC_ChannelCmd(ADC1, ADC_Channel_24, ENABLE); /* connected to potentiometer */
  //3设置DMA通道0连接ADC1，通道2连接TIM1
  /* Connect ADC1 to DMA1 channel 0 */
  SYSCFG_REMAPDMAChannelConfig(REMAP_DMA1Channel_ADC1ToChannel0);
  DMA_Init(DMA1_Channel0,
           BUFFER_ADDRESS,
           ADC1_DR_ADDRESS,
           BUFFER_SIZE,
           DMA_DIR_PeripheralToMemory,
           DMA_Mode_Circular,
           DMA_MemoryIncMode_Inc,
           DMA_Priority_High,
           DMA_MemoryDataSize_HalfWord);
 
  /* Connect DMA1 channel 2 to TIM1 */
  DMA_Init(DMA1_Channel2,
           BUFFER_ADDRESS,
           TIM1_CCR1_ADDRESS,
           BUFFER_SIZE,
           DMA_DIR_MemoryToPeripheral,
           DMA_Mode_Circular,
           DMA_MemoryIncMode_Inc,
           DMA_Priority_High,
           DMA_MemoryDataSize_HalfWord);
 
  /* DMA1 Channel0 enable */
  DMA_Cmd(DMA1_Channel0, ENABLE);
 
  /* DMA1 Channel2 enable */
  DMA_Cmd(DMA1_Channel2, ENABLE);
 
  /* DMA1 enable */
  DMA_GlobalCmd(ENABLE);
  //4设置TIM1 CH1输出PWM波
  /* configure TIM1 channel 1 as PWM Output */
  TIM1_OC1Init(TIM1_OCMode_PWM1,
               TIM1_OutputState_Enable,
               TIM1_OutputNState_Disable,
               0x7FF/* TIM1_Pulse */,
               TIM1_OCPolarity_Low,
               TIM1_OCNPolarity_Low,
               TIM1_OCIdleState_Reset,
               TIM1_OCNIdleState_Reset);
 
  /* Set TIM1 Autoreload value*/
  TIM1_SetAutoreload(0xFFF);
  //2M/4095=488.4HZ
  /* Enable TIM1 */
  TIM1_Cmd(ENABLE);
 
  //5 PD2 TIM1 CH1设置
  /* GPIO configuration: TIM1 channel 1 (PD2)*/
  GPIO_Init(GPIOD, GPIO_Pin_2 , GPIO_Mode_Out_PP_Low_Fast);
 
  //6 使能
  /* Enable TIM1 Outputs*/
  TIM1_CtrlPWMOutputs(ENABLE);
 
  /* Enable ADC1 DMA requests*/
  ADC_DMACmd(ADC1, ENABLE);
 
  /* Enable TIM1 DMA requests*/
  TIM1_DMACmd(TIM1_DMASource_Update, ENABLE);
 
  /* Start ADC1 Conversion using Software trigger*/
  ADC_SoftwareStartConv(ADC1);
 
  while (1)
  {}
}