%  DAQ Toolbox demonstration program
%
%   by Robert W. Ives, USNA
%  based on the daqdemo program by:
%  Thad B. Welch, CDR USN
%  28 July 1999
%
%  To start the program type "daq_minidemo" and push the "Enter" button.
%  A pause will then execute.  To continue, push the "Enter" button again.
%  To stop the program hit the CTRL-C buttons. 
%  The cpu may NOT be capable of processing the 8-44.1 ksamples/sec gathered
%  by the DAQ system.  Therefore, this program is intented for SHORT TERM 
%  OPERATIONS ONLY!  Failure to to adhere to this warning may result in
%  a system crash or an excessive program shutdown time.
%

fs=8000;     % sample frequency (in Hz)
N=512;       % number of samples grabbed w/each data acquisition

data=zeros(N,1);                % set aside space for N values

AI=analoginput('winsound');     % "AI" is the daq object, taken from the analog input
set(AI,'SampleRate',fs);        % set the sample rate of AI
chans=addchannel(AI,1);         % add a hardware channel input to provide data to AI
set(AI,'SamplesPerTrigger',N);  % take a group of N samples with every trigger
set(AI,'TriggerRepeat',inf);    % keep on triggering forever

start(AI);                      % start the data acquisition object
while AI.SamplesAcquired<N      % set up to acquire samples
   end
t=(0:N-1)*1/fs;                 % create a time vector for plotting
figure(1)                       % plots will appear in figure(1)
subplot(2,1,1)                  % upper plot
P=plot(t,data);                 % "P" is the identity of the top subplot
title('Real-time signal (sec)')
ylabel('Amplitude')
ylow=-1.2;, yhigh=1.2;          % the min & max y values on the y-axes
xlow=0;, xhigh=N/fs;            % the min & max x values on the x-axes
axis([xlow xhigh ylow yhigh])   % fix the range of values displayed
grid on
drawnow;                        % plot the data now 

subplot(2,1,2)                  % lower plot
revdata=flipud(data);           % this is the data, just time reversed
Q=plot(t,revdata);
ylabel('Time Reversed Amplitude')
xlabel('time (sec)');
axis([xlow xhigh ylow yhigh])   % fix the range of values displayed
grid on
drawnow;                        % place the values on the plot


set(gcf,'doublebuffer','on')
set(gcf,'Name','Data Acquisition Demonstration Program')
disp('The program is now set to run; press any key to begin.')
disp('     Press Ctrl-C to stop the program.')
pause           % wait until user pushes any key to continue

while 1
      data=peekdata(AI,N);  % peekdata returns the latest N samples from AI and
                            % stores them in the "data" variable
      revdata=flipud(data); % same as data, just time reversed
      %wavplay(revdata,fs,'async')
      getdata(AI,N);        % returns N samples from AI to the MATLAB workspace
      set(P,'ydata',data);  % P is the name of the upper subplot, insert the "data" 
                            %   values into its "ydata" attribute
      set(Q,'ydata',revdata); % Q is the name of the lower subplot
      drawnow;                % draw the two plots
end


stop(AI)