STM8L Exploration Kit Study Notes - Comprehensive Application (XVIII)

There are many peripherals used today, including DMA, TIM1, and ADC. Channel 24 of ADC1, namely PF1, is used to collect the voltage of the potentiometer, and is transferred to the buffer by channel 0 of DMA1. At the same time, channel 2 of DMA1 transfers the buffer to the TIM1 peripheral, namely the TIM1_CCR1H register, which can change the duty cycle of the PWM wave. We connect the PWM output end to LED3 on the board, so that the brightness of LED3 can be adjusted by the potentiometer. We took such a big detour, but we were able to learn a lot. Here is the code:
void main(void)
{
  //1 Enable clock
  /* 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 Set up 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 Set DMA channel 0 to connect to ADC1, channel 2 to connect to TIM1
  /* Connect ADC1 to DMA1 channel 0 */
  SYSCFG_REMAPDMAChannelConfig(REMAP_DMA1Channel_ADC1 ToChannel0);
  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);
  //4Set TIM1 CH1 to output PWM wave
  /* configure TIM1 channel 1 as PWM Output */
  TIM1_OC1Init(TIM1_OCMode_PWM1,
               TIM1_OutputState_Enable,
               TIM1_Out putNState_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)
  {}
}