STM32F4 DMA2D_R2M

图像处理的专门DMA

看一段示例代码

/**
* @brief  Initializes the DMA2D peripheral according to the specified parameters
*         in the DMA2D_InitStruct.
* @note   This function can be used only when the DMA2D is disabled.
* @param  DMA2D_InitStruct: pointer to a DMA2D_InitTypeDef structure that contains
*         the configuration information for the specified DMA2D peripheral.
* @retval None
*/
void DMA2D_Init(DMA2D_InitTypeDef* DMA2D_InitStruct)
{

uint32_t outgreen = 0;
uint32_t outred   = 0;
uint32_t outalpha = 0;
uint32_t pixline  = 0;

/* Check the parameters */
assert_param(IS_DMA2D_MODE(DMA2D_InitStruct->DMA2D_Mode));
assert_param(IS_DMA2D_CMODE(DMA2D_InitStruct->DMA2D_CMode));
assert_param(IS_DMA2D_OGREEN(DMA2D_InitStruct->DMA2D_OutputGreen));
assert_param(IS_DMA2D_ORED(DMA2D_InitStruct->DMA2D_OutputRed));
assert_param(IS_DMA2D_OBLUE(DMA2D_InitStruct->DMA2D_OutputBlue));
assert_param(IS_DMA2D_OALPHA(DMA2D_InitStruct->DMA2D_OutputAlpha));
assert_param(IS_DMA2D_OUTPUT_OFFSET(DMA2D_InitStruct->DMA2D_OutputOffset));
assert_param(IS_DMA2D_LINE(DMA2D_InitStruct->DMA2D_NumberOfLine));
assert_param(IS_DMA2D_PIXEL(DMA2D_InitStruct->DMA2D_PixelPerLine));

/* Configures the DMA2D operation mode */
DMA2D->CR &= (uint32_t)CR_MASK;
DMA2D->CR |= (DMA2D_InitStruct->DMA2D_Mode);

/* Configures the color mode of the output image */
DMA2D->OPFCCR &= ~(uint32_t)DMA2D_OPFCCR_CM;
DMA2D->OPFCCR |= (DMA2D_InitStruct->DMA2D_CMode);

/* Configures the output color */

if (DMA2D_InitStruct->DMA2D_CMode == DMA2D_ARGB8888)
{
outgreen = DMA2D_InitStruct->DMA2D_OutputGreen << 8;
outred = DMA2D_InitStruct->DMA2D_OutputRed << 16;
outalpha = DMA2D_InitStruct->DMA2D_OutputAlpha << 24;
}
else

if (DMA2D_InitStruct->DMA2D_CMode == DMA2D_RGB888)
{
outgreen = DMA2D_InitStruct->DMA2D_OutputGreen << 8;
outred = DMA2D_InitStruct->DMA2D_OutputRed << 16;
outalpha = (uint32_t)0x00000000;
}

else

if (DMA2D_InitStruct->DMA2D_CMode == DMA2D_RGB565)
{
outgreen = DMA2D_InitStruct->DMA2D_OutputGreen << 5;
outred = DMA2D_InitStruct->DMA2D_OutputRed << 11;
outalpha = (uint32_t)0x00000000;
}

else

if (DMA2D_InitStruct->DMA2D_CMode == DMA2D_ARGB1555)
{
outgreen = DMA2D_InitStruct->DMA2D_OutputGreen << 5;
outred = DMA2D_InitStruct->DMA2D_OutputRed << 10;
outalpha = DMA2D_InitStruct->DMA2D_OutputAlpha << 15;
}

else /* DMA2D_CMode = DMA2D_ARGB4444 */
{
outgreen = DMA2D_InitStruct->DMA2D_OutputGreen << 4;
outred = DMA2D_InitStruct->DMA2D_OutputRed << 8;
outalpha = DMA2D_InitStruct->DMA2D_OutputAlpha << 12;
}
DMA2D->OCOLR |= ((outgreen) | (outred) | (DMA2D_InitStruct->DMA2D_OutputBlue) | (outalpha));

/* Configures the output memory address */
DMA2D->OMAR = (DMA2D_InitStruct->DMA2D_OutputMemoryAdd);

/* Configure  the line Offset */
DMA2D->OOR &= ~(uint32_t)DMA2D_OOR_LO;
DMA2D->OOR |= (DMA2D_InitStruct->DMA2D_OutputOffset);

/* Configure the number of line and pixel per line */
pixline = DMA2D_InitStruct->DMA2D_PixelPerLine << 16;
DMA2D->NLR &= ~(DMA2D_NLR_NL | DMA2D_NLR_PL);
DMA2D->NLR |= ((DMA2D_InitStruct->DMA2D_NumberOfLine) | (pixline));

DMA2D_Init
DMA2D_InitStruct.DMA2D_Mode = DMA2D_R2M; // DMA2D->CR
DMA2D_InitStruct.DMA2D_CMode = DMA2D_RGB565; // DMA2D->OPFCCR
DMA2D_InitStruct.DMA2D_OutputGreen = Green_Value; // DMA2D->OCOLR
DMA2D_InitStruct.DMA2D_OutputBlue = Blue_Value; // DMA2D->OCOLR
DMA2D_InitStruct.DMA2D_OutputRed = Red_Value; // DMA2D->OCOLR
DMA2D_InitStruct.DMA2D_OutputAlpha = 0x0F; // DMA2D->OCOLR
DMA2D_InitStruct.DMA2D_OutputMemoryAdd = Xaddress; // DMA2D->OMAR

DMA2D_InitStruct.DMA2D_OutputOffset = 0; // DMA2D->OOR
DMA2D_InitStruct.DMA2D_NumberOfLine = 1; // DMA2D->NLR
DMA2D_InitStruct.DMA2D_PixelPerLine = Length; // DMA2D->NLR

Register to Memory比较简单，设置模式与输出color format，然后就是输出的颜色值，输出的地址（此例子直接给LCD），输出的offset已经解释过

没有FG（foreground）和 BG（background） 直接输出image到Memory