SPI W25X16读写问题

只看该作者 · 2014-10-1 21:54

W25X16一次只能写一页256Byte,这个函数可以一次写多页，我不懂这个Addr变量是什么意思，看上去是要对页取余，用来对其页码，可是W25X16数据手册上只写了不能连续写多页，那么分页操作只需要NumOfPage和NumOfSingle两个变量就可以了，为什么还要Addr呢，我这里搞不明白
#############################################################################
void SPI_FLASH_BufferWrite(u8* pBuffer, u32 WriteAddr, u16 NumByteToWrite)
{
  u8 NumOfPage = 0, NumOfSingle = 0, Addr = 0, count = 0, temp = 0;

  Addr = WriteAddr % SPI_FLASH_PageSize;
  count = SPI_FLASH_PageSize - Addr;
  NumOfPage =  NumByteToWrite / SPI_FLASH_PageSize;
  NumOfSingle = NumByteToWrite % SPI_FLASH_PageSize;

  if (Addr == 0) /* WriteAddr is SPI_FLASH_PageSize aligned  */
  {
if (NumOfPage == 0) /* NumByteToWrite < SPI_FLASH_PageSize */
{
   SPI_FLASH_PageWrite(pBuffer, WriteAddr, NumByteToWrite);
}
else /* NumByteToWrite > SPI_FLASH_PageSize */
{
   while (NumOfPage--)
   {
      SPI_FLASH_PageWrite(pBuffer, WriteAddr, SPI_FLASH_PageSize);
      WriteAddr +=  SPI_FLASH_PageSize;
      pBuffer += SPI_FLASH_PageSize;
   }

   SPI_FLASH_PageWrite(pBuffer, WriteAddr, NumOfSingle);
}
  }
  else /* WriteAddr is not SPI_FLASH_PageSize aligned  */
  {
if (NumOfPage == 0) /* NumByteToWrite < SPI_FLASH_PageSize */
{
   if (NumOfSingle > count) /* (NumByteToWrite + WriteAddr) > SPI_FLASH_PageSize */
   {
      temp = NumOfSingle - count;

      SPI_FLASH_PageWrite(pBuffer, WriteAddr, count);
      WriteAddr +=  count;
      pBuffer += count;

      SPI_FLASH_PageWrite(pBuffer, WriteAddr, temp);
   }
   else
   {
      SPI_FLASH_PageWrite(pBuffer, WriteAddr, NumByteToWrite);
   }
}
else /* NumByteToWrite > SPI_FLASH_PageSize */
{
   NumByteToWrite -= count;
   NumOfPage =  NumByteToWrite / SPI_FLASH_PageSize;
   NumOfSingle = NumByteToWrite % SPI_FLASH_PageSize;

   SPI_FLASH_PageWrite(pBuffer, WriteAddr, count);
   WriteAddr +=  count;
   pBuffer += count;

   while (NumOfPage--)
   {
      SPI_FLASH_PageWrite(pBuffer, WriteAddr, SPI_FLASH_PageSize);
      WriteAddr +=  SPI_FLASH_PageSize;
      pBuffer += SPI_FLASH_PageSize;
   }

   if (NumOfSingle != 0)
   {
      SPI_FLASH_PageWrite(pBuffer, WriteAddr, NumOfSingle);
   }
}
  }
}