File content as of revision 3:5702fea0c868:

#include "mbed.h"
#include "SDRAM_DISCO_F429ZI.h"

SDRAM_DISCO_F429ZI sdram;

DigitalOut led_green(LED1);
DigitalOut led_red(LED2);

Serial pc(USBTX, USBRX);

#define BUFFER_SIZE         ((uint32_t)0x0100)
#define WRITE_READ_ADDR     ((uint32_t)0x0800)

void FillBuffer(uint32_t *pBuffer, uint32_t BufferLength, uint32_t Offset);
uint8_t CompareBuffer(uint32_t* pBuffer1, uint32_t* pBuffer2, uint16_t BufferLength);

int main()
{
    uint32_t WriteBuffer[BUFFER_SIZE];
    uint32_t ReadBuffer[BUFFER_SIZE];
    FMC_SDRAM_CommandTypeDef SDRAMCommandStructure;
  
    pc.printf("\n\nSDRAM demo started\n");
    led_red = 0;

    // Fill the write buffer
    FillBuffer(WriteBuffer, BUFFER_SIZE, 0xA244250F);
  
    // Write buffer
    sdram.WriteData(SDRAM_DEVICE_ADDR + WRITE_READ_ADDR, WriteBuffer, BUFFER_SIZE);
    pc.printf("Write data DONE\n");

    // Issue self-refresh command to SDRAM device
    SDRAMCommandStructure.CommandMode            = FMC_SDRAM_CMD_SELFREFRESH_MODE;
    SDRAMCommandStructure.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK2;
    SDRAMCommandStructure.AutoRefreshNumber      = 1;
    SDRAMCommandStructure.ModeRegisterDefinition = 0;
    if (sdram.Sendcmd(&SDRAMCommandStructure) != HAL_OK) 
    {
      led_red = 1;
      error("BSP_SDRAM_Sendcmd FAILED\n");
    }
  
    // SDRAM memory read back access
    SDRAMCommandStructure.CommandMode = FMC_SDRAM_CMD_NORMAL_MODE;
    if (sdram.Sendcmd(&SDRAMCommandStructure) != HAL_OK) 
    {
      led_red = 1;
      error("BSP_SDRAM_Sendcmd FAILED\n"); 
    }

    while(1) {
      
      // Read back data from the SDRAM memory
      sdram.ReadData(SDRAM_DEVICE_ADDR + WRITE_READ_ADDR, ReadBuffer, BUFFER_SIZE); 
      pc.printf("\nRead data DONE\n");

      // Checking data integrity 
      if (CompareBuffer(WriteBuffer, ReadBuffer, BUFFER_SIZE) != 0)
      {
        led_red = !led_red;
        pc.printf("Write/Read buffers are different\n");
      }
      else
      {
        led_green = !led_green;
        pc.printf("Write/Read buffers are identical\n");
      }
  
      wait(1);
    }
}

/**
  * @brief  Fills buffer with user predefined data.
  * @param  pBuffer: pointer on the buffer to fill
  * @param  BufferLength: size of the buffer to fill
  * @param  Value: first value to fill on the buffer
  * @retval None
  */
void FillBuffer(uint32_t *pBuffer, uint32_t BufferLength, uint32_t Value)
{
  uint32_t tmpIndex = 0;

  /* Put in global buffer different values */
  for (tmpIndex = 0; tmpIndex < BufferLength; tmpIndex++ )
  {
    pBuffer[tmpIndex] = tmpIndex + Value;
  }
} 

/**
  * @brief  Compares two buffers.
  * @param  pBuffer1, pBuffer2: buffers to be compared.
  * @param  BufferLength: buffer's length
  * @retval 0: pBuffer2 identical to pBuffer1
  *         1: pBuffer2 differs from pBuffer1
  */
uint8_t CompareBuffer(uint32_t* pBuffer1, uint32_t* pBuffer2, uint16_t BufferLength)
{
  while (BufferLength--)
  {
    if (*pBuffer1 != *pBuffer2)
    {
      return 1;
    }

    pBuffer1++;
    pBuffer2++;
  }

  return 0;
}