stm-ledstrip : Driver and test routine for WS2811 RGB-LED

stm-ledstrip : Driver and test routine for WS2811 RGB-LED  

#include "ws2812.h"
#include <stm32f4xx.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_gpio.h>
#include <stm32f4xx_tim.h>
#include <stm32f4xx_dma.h>

static uint16_t PWM_Buffer[ PWM_BUFFER_SIZE ];
uint32_t frame_pos = 0;
int incomplete_return = 0;

void Update_Buffer( uint16_t* buffer );

static void start_dma( void )
{
  static DMA_InitTypeDef dma_init =
  { .DMA_BufferSize = PWM_BUFFER_SIZE, .DMA_Channel = DMA_Channel_5, .DMA_DIR =
    DMA_DIR_MemoryToPeripheral, .DMA_FIFOMode = DMA_FIFOMode_Disable,
    .DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull, .DMA_Memory0BaseAddr =
      (uint32_t) PWM_Buffer, .DMA_MemoryBurst = DMA_MemoryBurst_Single,
    .DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord, .DMA_MemoryInc =
      DMA_MemoryInc_Enable, .DMA_Mode = DMA_Mode_Circular,
    .DMA_PeripheralBaseAddr = (uint32_t) &TIM3->CCR4, .DMA_PeripheralBurst =
      DMA_PeripheralBurst_Single, .DMA_PeripheralDataSize =
      DMA_PeripheralDataSize_HalfWord, .DMA_PeripheralInc =
      DMA_PeripheralInc_Disable, .DMA_Priority = DMA_Priority_Medium };
  
  DMA_Init( DMA1_Stream2, &dma_init );
  DMA_Cmd( DMA1_Stream2, ENABLE );
  TIM_DMACmd( TIM3, TIM_DMA_CC4, ENABLE );
}

static void init_buffers( void )
{
  for ( int i = 0; i < PWM_BUFFER_SIZE; i++ )
  {
    PWM_Buffer[ i ] = 0;
  }
  for ( int i = 0; i < FRAMEBUFFER_SIZE; i++ )
  {
    ws2812_framebuffer[ i ].red = 0;
    ws2812_framebuffer[ i ].green = 0;
    ws2812_framebuffer[ i ].blue = 0;
  }
}

void ws2812_init( )
{
  init_buffers( );
  
  //InitStructures...
  GPIO_InitTypeDef GPIO_InitStructure;
  TIM_TimeBaseInitTypeDef TIM_TimeBase_InitStructure;
  TIM_OCInitTypeDef TIM_OC_InitStructure;
  NVIC_InitTypeDef nvic_init;
  
  //Clock für GPIO setzen
  RCC_AHB1PeriphClockCmd( RCC_AHB1Periph_GPIOC, ENABLE );
  
  //Clock für TIM4 setzen
  RCC_APB1PeriphClockCmd( RCC_APB1Periph_TIM3, ENABLE );
  
  //GPIO_PIN konfigurieren
  
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init( GPIOC, &GPIO_InitStructure );
  
  //GPIO Alternate function verbinden
  GPIO_PinAFConfig( GPIOC, GPIO_PinSource9, GPIO_AF_TIM3 );
  
  TIM_TimeBase_InitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBase_InitStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBase_InitStructure.TIM_Period = 104;
  TIM_TimeBase_InitStructure.TIM_Prescaler = 0;
  TIM_TimeBaseInit( TIM3, &TIM_TimeBase_InitStructure );
  
  TIM_OC_InitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OC_InitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
  TIM_OC_InitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Set;
  TIM_OC_InitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OC_InitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
  TIM_OC_InitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OC_InitStructure.TIM_OutputNState = TIM_OutputNState_Disable;
  TIM_OC_InitStructure.TIM_Pulse = 0;
  TIM_OC4Init( TIM3, &TIM_OC_InitStructure );
  
  TIM_CtrlPWMOutputs( TIM3, ENABLE );
  
  TIM_OC4PreloadConfig( TIM3, TIM_OCPreload_Enable );
  TIM_ARRPreloadConfig( TIM3, ENABLE );
  
  TIM_CCxCmd( TIM3, TIM_Channel_4, TIM_CCx_Enable );
  TIM_Cmd( TIM3, ENABLE );
  
  // DMA
  RCC_AHB1PeriphClockCmd( RCC_AHB1Periph_DMA1, ENABLE );
  TIM_DMACmd( TIM3, TIM_DMA_CC4, ENABLE );
  DMA_ITConfig( DMA1_Stream2, DMA_IT_HT, ENABLE );
  DMA_ITConfig( DMA1_Stream2, DMA_IT_TC, ENABLE );
  
  start_dma( );
  
  // NVIC for DMA
  nvic_init.NVIC_IRQChannel = DMA1_Stream2_IRQn;
  nvic_init.NVIC_IRQChannelPreemptionPriority = 4;
  nvic_init.NVIC_IRQChannelSubPriority = 0;
  nvic_init.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init( &nvic_init );
}

// writes the pwm values of one byte into the array which will be used by the dma
static inline void color2pwm( uint16_t ** const dest, const uint8_t color )
{
  uint8_t mask = 0x80;
  
  do
  {
    if ( color & mask )
    {
      * *dest = 49;
    }
    else
    {
      * *dest = 20;
    }
    *dest += 1;
    mask >>= 1;
  }while ( mask != 0 );
}

void Update_Buffer( uint16_t* buffer )
{
  struct led *framebufferp;
  uint32_t i, j;
  uint16_t * bufp;
  
  for ( i = 0; i < ( PWM_BUFFER_SIZE / 2 ) / 24; i++ )
  {
    if ( incomplete_return )
    {
      incomplete_return = 0;
      for ( j = 0; j < 24; j++ )
      {
        buffer[ i * 24 + j ] = 0;
      }
      
    }
    else
    {
      if ( frame_pos == FRAMEBUFFER_SIZE )
      {
        incomplete_return = 1;
        frame_pos = 0;
        
        for ( j = 0; j < 24; j++ )
        {
          buffer[ i * 24 + j ] = 0;
        }
      }
      else
      {
        framebufferp = &ws2812_framebuffer[ frame_pos++ ];
        bufp = buffer + ( i * 24 );
        
        // edit here to change order of colors in "ws2812_framebuffer" (0x00RRGGBB, 0x00GGBBRR, etc)
        // the chip needs G R B
        color2pwm( &bufp, framebufferp->green ); // green
        color2pwm( &bufp, framebufferp->red ); // red
        color2pwm( &bufp, framebufferp->blue ); // blue
      }
    }
  }
}

void DMA1_Stream2_IRQHandler( void )
{
  // Half-Transfer completed
  if ( DMA_GetITStatus( DMA1_Stream2, DMA_IT_HTIF2 ) )
  {
    DMA_ClearITPendingBit( DMA1_Stream2, DMA_IT_HTIF2 );
    Update_Buffer( PWM_Buffer );
  }
  
  // Transfer completed
  if ( DMA_GetITStatus( DMA1_Stream2, DMA_IT_TCIF2 ) )
  {
    DMA_ClearITPendingBit( DMA1_Stream2, DMA_IT_TCIF2 );
    Update_Buffer( PWM_Buffer + ( PWM_BUFFER_SIZE / 2 ) );
  }
  
}