Q. The older interrupt function set ....
   A821_InstallIrq(), A821_AD_INT_Start(), A821_AD_INT_Stop()
   A821_GetIntCount(), A821_GetBuffer(), A821_GetFloatBuffer()
   does not works with the newest version of driver.
A. The Interrupt-Buffer had been changed to Dynamic-Allocate,
   thus, the Interrupt-Buffer will be removed after users call
   the A821_AD_INT_Stop() function.
   Solution 1: Users have to call the function A821_GetBuffer()
               before stop the interrupt.
   Solution 2: Users have to uses the older version of driver.