%$Revision 0.992b 08/21/2002
%written by: Alan Chen
%contact: alanchen@mit.edu
%
%
%AOI (AOI??)
%   AOI ( DATA, CHANNELS, FREQUENCY ) is a routine that interfaces the NI-DAC board
%     via the COMEDI library.  AOI enables simultaneous input and output.  
%
%   DATA is the data matrix to be outputted by the COMEDI device.  The channels are
%       column aligned.  DATA should be voltages, in volts.
%
%   CHANNELS is a row vector containing the enumeration of input channels to be
%       sampled.
%
%   FREQUENCY is the sampling rate of the input/output signals, in Hz.
%
%   The output of AOI is the data matrix that was sampled in the input channels (in
%       Volts, I think), over the same period that the output was made to the output
%       channels.
%
%   Example:
%
%       The example below will output the column [ 1 2 3 4 5 ]' and then the column
%       [ 6 7 8 9 0 ]' to output channels 0 through 5 at an interval of 10ms (100 Hz).
%       It will also acquire data in input channels 0, 1, 3, 5 at the same instances
%       when the output was made and the output will be a 2 by 4 array of the sampled
%       voltages (in volts) in those channels.
%
%	output_data_ch1 = [ 1 2 3 4 5 ]';
%       output_data_ch2 = [ 6 7 8 9 0 ]';
%       input_channels = [ 0 1 3 5 ];
%       frequency = 100;
%       input_data = aoi( [ output_data_ch1 output_data_ch2 ], input_channels, frequency); 
%