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Basic analog to digital converters

This demo is straight forward, it is designed to send voltages to the digital to analogue converters. It also reads them back with an internal or physical loopback.

function DatapixxAdcBasicDemo(internalLoopback)
% DatapixxAdcBasicDemo([internalLoopback=1])
% Demonstrates the basic functions of the Datapixx analog to digital converters.
% Prints the input voltage range, and current input voltage, for all channels.
% Optional argument:
% internalLoopback = 1 if DAC outputs should be internally looped back to ADC inputs
%                  Otherwise the ADC converts the actual voltages on the db-25 pins
% Also see: DatapixxAdcAcquireDemo, DatapixxAdcStreamDemo
% History:
% Oct 1, 2009  paa     Written
% Oct 29, 2014 dml     Revised 

AssertOpenGL;   % We use PTB-3

% Get internal loopback argument
if nargin < 1
    internalLoopback = [];
if isempty(internalLoopback)
    internalLoopback = 1;

% Open Datapixx, and stop any schedules which might already be running
Datapixx('RegWrRd');    % Synchronize Datapixx registers to local register cache

% DAC outputs can be looped back to ADC inputs inside the DATAPixx.
% There are 4 DAC channels, and 16 ADC channels, plus 2 ADC reference channels,
% so the internal loopback maps DAC outputs to multiple ADC inputs:
%   DAC0 => ADC0/2/4/6/8/10/12/14
%   DAC1 => ADC1/3/5/7/9/11/13/15
%   DAC2 => REF0
%   DAC3 => REF1
% Even if we are not doing an internal loopback, we'll still program the DAC outputs.
% This allows us to do an _external_ loopback;
% ie: wire the DAC outputs to the ADC inputs right on the db-25 connector.
% We'll arbitrarily program the 4 DAC channels to 5V, 2.5V, -2.5V, -5V
if (internalLoopback == 1)
    Datapixx('EnableDacAdcLoopback');   % We'll read back what's on the DAC outputs
    Datapixx('DisableDacAdcLoopback');  % We'll read what's really on the input db-25
Datapixx('SetDacVoltages', [0:3 ; 5 2.5 -2.5 -5]);
Datapixx('EnableAdcFreeRunning');       % ADC's convert continuously
Datapixx('RegWrRd');    % Write local register cache to hardware
Datapixx('RegWrRd');    % Give time for ADCs to convert, then read back data to local cache

% Show how many ADC channels are in the Datapixx
nChannels = Datapixx('GetAdcNumChannels');
fprintf('\nDatapixx has %d ADC channels\n\n', nChannels);

% Show the input voltage range, and current value, for each ADC channel
adcRanges = Datapixx('GetAdcRanges');
adcDataVoltages = Datapixx('GetAdcVoltages');
for channel = 0:nChannels-1
    fprintf('Channel %d input range is %g to %g Volts, current value is %g Volts\n',...
        channel, adcRanges(1, channel+1), adcRanges(2, channel+1), adcDataVoltages(channel+1));

% Job done
fprintf('\n\nDemo completed\n\n');
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