Trying to read EEG data from hardware using cypress .NET library that handles the CyUSB.

Hello,

I am using an electroencephalogram (EEG) that uses a CyUSB.sys driver. I am looking to get the incoming EEG data into MATLAB. The code is under the following. I have used Cypress CyUSB .NET DLL Programmer's Reference to write the code ( http://www.cypress.com/?docID=45233 ). Everyting works untill last line, Buf is a byte type I thought using a 'uint' should do the job. I do not know how to convert C# code in the programmers reference to MATLAB code.

CODE:

try
    
    CyUSBdll = NET.addAssembly('C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\bin\CyUSB.dll');
catch error
    error.message
    if(isa(error,'NET.NetException'))
        e.ExceptionObject
    else
        disp('CyUSB.dll already loaded');
        return;
    end
end
%%USB Device Select
% Create a list of USB devices
usbDevices = CyUSB.USBDeviceList(CyUSB.CyConst.DEVICES_CYUSB);
device=usbDevices.Item(0);



CEP=device.ControlEndPt;
CEP.Target=CyUSB.CyConst.TGT_DEVICE;
CEP.ReqType=CyUSB.CyConst.REQ_VENDOR;  
CEP.Direction=CyUSB.CyConst.DIR_FROM_DEVICE;  
CEP.ReqCode=0xB0;  
CEP.Value=0;
CEP.Index=0;
len=64;
buf=uint(len);
CEP.XferData(ref buf, ref len);

Error:

Last line is giving me this error

[vishwas dalal]

Also, in the last line if I change it to this

' CEP.XferData(buf, len);'

the error now is

No method 'XferData' with matching signature found for class 'CyUSB.CYControlEndPoint'.

[Walter Roberson]

buf = zeros(1, len, 'uint8');

but the "ref buf" needs to be changed. Is the code expecting to receive a pointer to a buffer?

https://www.mathworks.com/help/matlab/matlab_external/limitations-to-net-support.html

constructors with ref arguments not supported

pointer arguments not supported

[vishwas dalal]

Hello,

len=64;

buf=uint(len);

CEP.XferData( buf, len);

has no errors but the program runs indefinatly. Ctrl+C also doenot stop the execution, i do not know if the data is coming in or is it stuck in some kind of loop.

[Walter Roberson]

MATLAB has no function named uint so I do not know what your code might be doing.

https://www.infineon.com/cms/en/design-support/tools/sdk/usb-controllers-sdk/ez-usb-fx3-software-development-kit/

indicates a file that includes the C++ api. It would be more robust to use that, as MATLAB can call that relatively directly; see https://www.mathworks.com/help/matlab/call-cpp-library-functions.html

[vishwas dalal]

Hi Walter,

My bad, the code that is working is the one you told, which is:

-len=64;

-buf = zeros(1, len, 'uint8');

-CEP.XferData( buf, len);

But it just doesnot stop, thanks for the input.

Answer 1

[Rafael Costa]

Hello, I come here to give my contribution on the CyUSB.dll library linking problem in MATLAB, first of all, make sure that the CyUSB.dll class library is the latest 1.2.3.0(EZ-USB FX3 SDK), install the latest drivers for the proper functioning of the device. Read carefully the Cypress CyUSB .NET DLL programmer's reference manual, in the C# language, the 'as' operator is used for casting objects in another class, in Matlab it is somehow done automatically I think.

Use methodsview() to see what a method signature looks like for each class you want to use: methodsview(device), methodsview(outEndpoint), etc.

Try to run according to the code below, on my data acquisition device which contains the chip cy7c68013a-56pvxc it worked correctly, my device is a high-speed USB 2.0 device and transmits packets in bulk transfers (512 bytes). You can change the size of packets on each endpoint using method in a class, do it correctly and carefully.

asm = NET.addAssembly('C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\bin\CyUSB.dll');
usbDevices = CyUSB.USBDeviceList(CyUSB.CyConst.DEVICES_CYUSB);

device=usbDevices.Item(1204,241); %% VID & PID (0x04b4, 0x00F1)
outEndpoint = device.EndPointOf(2); % 0x02
inEndpoint = device.EndPointOf(134); %% 0x86

%% device %% to see the properties of the class
%% methodsview(device) %% to see the methods and methods signatures

outEndpoint.TimeOut = 1000;
inEndpoint.TimeOut = 1000;

%% methodsview(inEndpoint) %% to see the methods and methods signatures

XFERSIZE = 512;
len = 512;
buf = zeros(1, XFERSIZE,'uint8');

ct_loop = 9; %% amounts of readings that will be performed on the device
ct_bgn = 1;
ct_end = len;

inData_cast = zeros(1,len); 
data_out = zeros(1, ct_loop*len);
inData_raw{ct_loop} = 0;

for i = 1:ct_loop
    [~,inData_raw{i},~] = inEndpoint.XferData(buf, len); %% device to host
end

for i = 1:ct_loop
    inData_cast = cast(inData_raw{i}, 'uint8');
    data_out(ct_bgn : ct_end) = inData_cast;
    ct_bgn = ct_end + 1;
    ct_end = ct_end + len;
end

plot(data_out); %% it is only to see the raw data concatenated, it is necessary a long treatment or processing of the obtained data

device.Dispose();

clear all;

[edeson]

how to use the asynchronous IO function such as BeginDataXfer/FinishDataXfer( ) /WaitForXfer function