%Find out which port the Arduino is using.  One way is to use the Arduino IDE.

% These are the commands you must execute in matlab to initialize for a virtual serial port COM5 on a PC.

% global a; a = serial(‘COM5′,’baudrate’,115200);fopen(a)

%Mac, for example:  global a; a = serial(‘/dev/tty.usbmodem1431′,’BaudRate’,115200); fopen(a)

 function[] = setvoltageDC(channel,voltage)

 

global a

 

if voltage > 10

voltage = 10.0;

elseif voltage < -10

voltage = -10.0;

 end

switch channel

case 1

n1 = 19;

n2=0;

m1=1;

m2=0;

case 2

n1 = 18;

n2=0;

m1=1;

m2=0;

case 3

n1 = 17;

n2=0;

m1=1;

m2=0;

case 4

n1 = 16;

n2=0;

m1=1;

m2=0;

case 5

n1 = 0;

n2=19;

m1=0;

m2=1;

case 6

n1 = 0;

n2=18;

m1=0;

m2=1;

case 7

n1 = 0;

n2=17;

m1=0;

m2=1;

case 8

n1 = 0;

n2=16;

m1=0;

m2=1;

    otherwise

        disp(‘INVALID CHANNEL’)

end

if voltage >= 0

dec16 = round((2^15-1)*voltage/10); %Decimal equivalent of 16 bit data 

else

    dec16 = round(2^16 – abs(voltage)/10 * 2^15); %Decimal equivalent of 16 bit data 

end

bin16 = de2bi(dec16,16,2,‘left-msb’); %16 bit binary

d1=bi2de(fliplr(bin16(1:8))); %first 8 bits

d2=bi2de(fliplr(bin16(9:16))); %second 8 bits

%disp([255,254,253,n1,d1*m1,d2*m1,n2,d1*m2,d2*m2]); %uncomment to check what’s being sent to the Arduino

pause(.005);

fwrite(a,[255,254,253,n1,d1*m1,d2*m1,n2,d1*m2,d2*m2]);

while a.BytesAvailable

fscanf(a,‘%e’);

end

end