DSP board initialzation

Using Download button it's possible to initialize DSP board and download a DSP program into it. It is necessary to do it every time you turn on the microscope, because during download DAC initial values and ADC calibration is performed. It is not recommended to download the program into DSP board during scanning process. After downloading all current parameters, configured by user (piezomanipulator position, tunneling current setting, feedback gains etc) will be restored.