File content as of revision 2:19c2835ce409:

#include "mbed.h"
#define USE_STM32746G_DISCOVERY
#include "stm32f7xx_hal.h"
#include "stm32746g_discovery.h"
#include "stm32746g_discovery_sd.h"
#include "string.h"
#include "stm32746g_discovery_lcd.h"
#include "ff_gen_drv.h"
#include "sd_diskio.h"

#define FRAME_BUFFER    0xC0000000
#define SD_IN_BUFFER    0xC0140000
#define SD_OUT_BUFFER   0xC0280000

FATFS SDFatFs;
FIL MyFile;




static void LCD_LL_ConvertFrameToARGB8888(void *pSrc, void *pDst);
static void LCD_LL_ConvertFrameToRGB888(void *pSrc, void *pDst);
extern SD_HandleTypeDef uSdHandle;
DMA2D_HandleTypeDef hdma2d_disco;

Serial pc(USBTX, USBRX);
uint32_t i = 0, image_width = 0, image_height = 0;
const char image_header[] = "P6\n# Generated by STM32\n480 272\n255\n";

char SDPath[4];
char text [40];
char c;
int main(void)
{
    FRESULT res;
    uint32_t  bytesread;
    uint32_t line_cnt=0;
    pc.baud(115200);

    BSP_LCD_Init();
    BSP_LCD_DisplayOff();
    BSP_LCD_LayerDefaultInit(0, FRAME_BUFFER);
    BSP_LCD_SelectLayer(0);
    BSP_LCD_DisplayOn();

    FATFS_LinkDriver(&SD_Driver, SDPath);

    res = f_mount(&SDFatFs, (TCHAR const*)SDPath, 0);
    if(res!= FR_OK)
        pc.printf("Failed to mount SD\n");

    res = f_open(&MyFile, "image.ppm",  FA_READ);
    if(res!= FR_OK)
        pc.printf("Failed to open file\n");
    
    // Read image header and get image size
    while(res==FR_OK) {
        res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
        if (c!='#')
            line_cnt++;
        if(line_cnt==2) {
            text[0] = c;
            res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
            i = 1;
            while(c!=' ') {
                text[i]=c;
                res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
                i++;
            }
            text[i]=0;
            image_width = atoi(text);
            res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
            i = 0;
            while(c!='\n') {
                text[i]=c;
                res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
                i++;
            }
            text[i]=0;
            image_height = atoi(text);
        } else {
            while(c!='\n')
                res = f_read(&MyFile, &c, 1, (UINT*)&bytesread);
        }
        if(line_cnt == 3)
            break;

    }

    if(image_width != 480 || image_height != 272)
        pc.printf("Image size should be 480x272");
        
    // Read image as 512 byte blocks
    for(i = 0; i < image_width*image_width*3; i = i + 512) {
        res = f_read(&MyFile, (uint8_t *)(SD_IN_BUFFER+i) , 512, (UINT*)&bytesread);
    }
    
    // Correct color order
    for(i = 0; i < image_width*image_width*3; i = i + 3) {
        c = *(char *)(SD_IN_BUFFER+i+2);
        *(char *)(SD_IN_BUFFER+i+2)= *(char *)(SD_IN_BUFFER+i);
        *(char *)(SD_IN_BUFFER+i) = c;
    }
    f_close(&MyFile);
    
    // Print image on LCD
    LCD_LL_ConvertFrameToARGB8888((uint32_t *)(SD_IN_BUFFER), (uint32_t *)(FRAME_BUFFER));

    
    // Transfer image to a buffer
    LCD_LL_ConvertFrameToRGB888((uint32_t *)(FRAME_BUFFER), (uint32_t *)(SD_OUT_BUFFER));
    
    // Correct color order
    for(i = 0; i < image_width*image_width*3; i = i + 3) {
        c = *(char *)(SD_OUT_BUFFER+i+2);
        *(char *)(SD_OUT_BUFFER+i+2)= *(char *)(SD_OUT_BUFFER+i);
        *(char *)(SD_OUT_BUFFER+i) = c;
    }
    
    res = f_open(&MyFile, "image_ou.ppm",   FA_CREATE_ALWAYS | FA_WRITE);
    if(res!= FR_OK)
        pc.printf("Failed to open file\n");

    // Write image header
    res = f_write(&MyFile, image_header, sizeof(image_header), &bytesread);
    if(res!= FR_OK)
        pc.printf("Failed to write file 1\n");
        
    // Write image as 512 byte blocks
    for(i = 0; i < 480*272*3; i = i + 512) {
        res = f_write(&MyFile, (uint8_t *)(SD_OUT_BUFFER+i), 512, &bytesread);
        if(res!= FR_OK)
            pc.printf("Failed to write file\n");
    }

    pc.printf("Done!\n");
    f_close(&MyFile);
    FATFS_UnLinkDriver(SDPath);

    while (1) {
    }
}
extern "C" {
    void BSP_SDMMC_IRQHandler(void)
    {
        HAL_SD_IRQHandler(&uSdHandle);
    }
    void BSP_SDMMC_DMA_Tx_IRQHandler(void)
    {
        HAL_DMA_IRQHandler(uSdHandle.hdmatx);
    }
    void BSP_SDMMC_DMA_Rx_IRQHandler(void)
    {
        HAL_DMA_IRQHandler(uSdHandle.hdmarx);
    }
    static void LCD_LL_ConvertFrameToARGB8888(void *pSrc, void *pDst)
    {
        /* Enable DMA2D clock */
        __HAL_RCC_DMA2D_CLK_ENABLE();

        /* Configure the DMA2D Mode, Color Mode and output offset */
        hdma2d_disco.Init.Mode         = DMA2D_M2M_PFC;
        hdma2d_disco.Init.ColorMode    = DMA2D_ARGB8888;
        hdma2d_disco.Init.OutputOffset = 0;

        /* Foreground Configuration */
        hdma2d_disco.LayerCfg[1].AlphaMode = DMA2D_NO_MODIF_ALPHA;
        hdma2d_disco.LayerCfg[1].InputAlpha = 0xFF;
        hdma2d_disco.LayerCfg[1].InputColorMode = CM_RGB888;
        hdma2d_disco.LayerCfg[1].InputOffset = 0;

        hdma2d_disco.Instance = DMA2D;

        /* DMA2D Initialization */
        if(HAL_DMA2D_Init(&hdma2d_disco) == HAL_OK) {
            if(HAL_DMA2D_ConfigLayer(&hdma2d_disco, 1) == HAL_OK) {
                if (HAL_DMA2D_Start(&hdma2d_disco, (uint32_t)pSrc, (uint32_t)pDst, 480, 272) == HAL_OK) {
                    /* Polling For DMA transfer */
                    HAL_DMA2D_PollForTransfer(&hdma2d_disco, 10);
                }
            }
        } else {

        }
    }
    static void LCD_LL_ConvertFrameToRGB888(void *pSrc, void *pDst)
    {
        /* Enable DMA2D clock */
        __HAL_RCC_DMA2D_CLK_ENABLE();

        /* Configure the DMA2D Mode, Color Mode and output offset */
        hdma2d_disco.Init.Mode         = DMA2D_M2M_PFC;
        hdma2d_disco.Init.ColorMode    = DMA2D_RGB888;
        hdma2d_disco.Init.OutputOffset = 0;

        /* Foreground Configuration */
        hdma2d_disco.LayerCfg[1].AlphaMode = DMA2D_NO_MODIF_ALPHA;
        hdma2d_disco.LayerCfg[1].InputAlpha = 0xFF;
        hdma2d_disco.LayerCfg[1].InputColorMode = CM_ARGB8888;
        hdma2d_disco.LayerCfg[1].InputOffset = 0;

        hdma2d_disco.Instance = DMA2D;

        /* DMA2D Initialization */
        if(HAL_DMA2D_Init(&hdma2d_disco) == HAL_OK) {
            if(HAL_DMA2D_ConfigLayer(&hdma2d_disco, 1) == HAL_OK) {
                if (HAL_DMA2D_Start(&hdma2d_disco, (uint32_t)pSrc, (uint32_t)pDst, 480, 272) == HAL_OK) {
                    /* Polling For DMA transfer */
                    HAL_DMA2D_PollForTransfer(&hdma2d_disco, 10);
                }
            }
        } else {

        }
    }

}