function prr = readprr(filename)

% Brian Schlining
% 24 Jan 2000

%===========
% Open File
%===========
if ~nargin
   
   [infile inpath] = uigetfile('*.bin','Select binary prr data file',0,0);
   
   if infile == 0
      return                            % Return if CANCEL is selected
   end
   
   filename = [inpath infile];
   
end

fid = fopen(filename,'r','b');			 % Read a binary file as big-endian

if fid <= 0
   
   warning(['Unable to open ' filename])
   out = [];
   return
   
end

%======================
% Read the binary data
%======================
fseek(fid,0,1);					 % Move pointer to the end of the file
stop = ftell(fid);				 % Get the length of the file in bytes
frewind(fid);						 % Rewind back to the beginning of the file

n   = 0;
OK  = 1;
SRE = 9.54*10^-6;		  	 		 % Smallest resolvabel element (for 10 v scale) in volts

while OK
   
   n               = n + 1;
   address(n,1)    = fread(fid, 1, 'int8');
   numChannel(n,1) = fread(fid, 1, 'int8');
   staleFlag       = ones(1,numChannel(n)) * NaN;	% Initialize memory
   gain            = staleFlag;
   count           = staleFlag;
   
   for i = 1:numChannel(n,1)								% Loop through each channel in a data block
      
      staleFlag(i) = fread(fid, 1, 'ubit1');
      gain(i)      = 4^(fread(fid, 1, 'ubit2')*2);
      count(i)     = fread(fid, 1, 'bit13');
      
   end
   
   data{n}     = count.*SRE.*256./gain;				% Convert counts to volts
   checkSum(n) = fread(fid, 1, 'int8');
   pos         = ftell(fid);
   
   if pos >= stop - 5
      OK = 0;
   end
   
end

fclose(fid);													% Close the file

u         = unique(address);								% Find the different cpus
numCpu    = length(u);										% Count the number of cpus
numRecord = length(data)/numCpu;							% Count the number of data records

for i = 1:numCpu
   prr(i).src     = filename;
   good           = find(address == u(i));			% Find the data for each cpu
   prr(i).address = u(i);
   prr(i).volts   = reshape([data{good}]',numChannel(good(1)), numRecord)';
   
end