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rINSTCONTROL/@MyNewportUsbComm/MyNewportUsbComm.m
48802f884580TekRSA-Freq-vs-Time

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MyNewportUsbComm.m
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classdef MyNewportUsbComm < MySingleton
properties (GetAccess = public, SetAccess = private)
isbusy = false % driver in use
QueryData % query buffer
end
properties (Access = public)
Usb % Instance of Newport.USBComm.USB class
end
methods(Access = private)
% The constructor of a singleton class should only be invoked from
% the instance method.
function this = MyNewportUsbComm()
disp(['Creating a new instance of ' class(this)])
this.QueryData = System.Text.StringBuilder(64);
loadLib(this);
end
end
methods(Access = public)
% Load dll
function loadLib(this)
dll_path = which('UsbDllWrap.dll');
if isempty(dll_path)
error(['UsbDllWrap.dll is not found. This library ',...
'is a part of Newport USB driver and needs ',...
'to be present on Matlab path.'])
end
NetAsm = NET.addAssembly(dll_path);
% Create an instance of Newport.USBComm.USB class
Type = GetType(NetAsm.AssemblyHandle,'Newport.USBComm.USB');
this.Usb = System.Activator.CreateInstance(Type);
end
function str = query(this, addr, cmd)
% Check if the driver is already being used by another process.
% A race condition with various strange consequences is
% potentially possible if it is.
if this.isbusy
warning('NewportUsbComm is already in use')
end
this.isbusy = true;
% Send query using the QueryData buffer
stat = Query(this.Usb, addr, cmd, this.QueryData);
if stat == 0
str = char(ToString(this.QueryData));
else
str = '';
warning('Query to Newport usb driver was unsuccessful.');
end
this.isbusy = false;
end
end
methods(Static)
% Concrete implementation of the singleton constructor.
function this = instance()
persistent UniqueInstance
if isempty(UniqueInstance) || ~isvalid(UniqueInstance)
this = MyNewportUsbComm();
UniqueInstance = this;
else
this = UniqueInstance;
end
end
end
end
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