Software (SW) APIs require a device driver of the same generation.
Beyond the SW APIs (used for the communication between the host computer and the USB FX2 microcontroller), another set of firmware (FW) API exists: they are called "API Commands". The SW program running on host computer sends API commands to the USB FX2 microcontroller and/or Xilinx MicroBlaze embedded processor by means of the following SW API functions:

• generation 2: TE0300_SendCommand(…, command, …);
• generation 3: TE_USB_FX2_SendCommand(..., command, …).

The USB FX2 microcontroller and/or Xilinx MicroBlaze soft embedded processor is(/are) able to execute the command. Skilled users can extend the FW API Command modifying USB FX2 microcontroller firmware (and MicroBlaze SW if necessary, but in many case is not necessary).

Generation 2

DLL files:

• DEWESoft_API

Documentation:

• UM-TE_USB_API.pdf

This API

• uses a C interface, and therefore can be easily bound to Python;
• uses handles;
• cannot set any time-out for SetData() function. In fact, it is internally set to 1000 ms.
• cannot set the driver buffer dimension;
• is closed source, and therefore cannot be extended or enhanced.

A binding from Python to DEWESoft TE USB API is possible through the ctypes function library.

Generation 3

Trenz Electronic USB FX2 APIs

1. TE_USB_FX2_CyAPI API for C/C++
2. TE_USB_FX2_CyUSB API for .NET Framework

are based on the Cypress CyUSB.sys device driver (renamed as TE_USB_FX2_xx.sys) and respectively on

1. Cypress CyAPI APIs for C/C++
2. Cypress CyUSB API for .NET Framework

distributed with the Cypress SuiteUSB 3.4 (or later).
Trenz Electronic USB FX2 APIs do not use handles.

TE_USB_FX2_CyAPI APIs (C++)

API files:

• TE_USB_FX2_CyAPI
  TE_USB_FX2_CyAPI.dll is open source but CyAPI.lib is not. Nevertheless, its source code can be requested from Cypress under non disclosure agreement.

Documentation:

• UM-TE_USB_API.cpp Reference Manual
• UM-TE_USB_API.cpp Porting Guide

Cypress CyAPI (CyAPI.lib) APIs for C/C++:

• are static libraries (embedded in TE_USB_FX2_CyAPI.dll and therefore not required by the user program);
• can be used by both managed (with .NET) C++ code and by unmanaged (without .NET) C++ code;
• have one version for Microsoft Windows 32 bit;
• have one version for Microsoft Windows 64 bit;
• have same name to ease code portability.

Trenz Electronic TE_USB_FX2_CyAPI.dll's for C/C++:

• are dynamic libraries;
• can be used by both managed (with .NET) C++ code and by unmanaged (without .NET) C++ code;
• have one version for Microsoft Windows 32 bit;
• have one version for Microsoft Windows 64 bit;
• have same name to ease code portability;
• are open source (can be modified and extended).

TE_USB_FX2_CyAPI APIs are not pure extern C code libraries because an external creation of a class instance defined in CyAPI.h (CyAPI.lib) is required.
Advantage:

• Possible to directly access CyAPI.lib classes and functions to extend Trenz Electronic TE_USB_FX2_CyAPI.dll libraries with other classes and functions (for example Plug and play functions and asynchronous multithread bulk data trasfers).
• Support of multi-thread and multi-process programming.

Disadvantage:

• A binding from Python to TE_USB_FX2_CyAPI APIs is possible by resorting to a wrapper (e.g. through SWIG) rather than just the ctypes function library. This wrapper is not provided by Trenz Electronic.

A pure extern C code library version of TE_USB_FX2_CyAPI APIs (codename: simplified TE_USB_FX2_CyAPI APIs) is available for developers.
Advantage:

• Binding to Python requires just the ctypes function library rather than by resorting to a wrapper.

Disadvantages:

• Impossible to directly access CyAPI.lib classes and functions to extend Trenz Electronic TE_USB_FX2_CyAPI.dll libraries with other classes and functions;
• No support of multi-thread programming (but still support of multi-process programming).

TE_USB_FX2_CyUSB API (.NET)

API files:

• TE_USB_FX2_CyUSB
  TE_USB_FX2_CyUSB.dll is open source but CyUSB.dll is not. Nevertheless, its source code can be requested from Cypress under non disclosure agreement.

Documentation:

• UM-TE_USB_API.cs Reference Manual
• UM-TE_USB_API.cs Porting Guide

Cypress CyUSB (CyUSB.dll) API for .NET Framework:

• is a dynamic library (not embedded in TE_USB_FX2_CyAPI.dll and therefore required by the user along with TE_USB_FX2_CyAPI.dll);
• classes and functions can be directly accessed from the application to extend Trenz Electronic TE_USB_FX2_CyUSB.dll libraries with other classes and functions;
• has only one version for both Microsoft Windows 32 and 64 bit.
• is not a COM (Component Object Model) object, so it cannot be called by C++ or Python code;
• is a managed Microsoft .NET class library that can be used with any programming language of the .NET Framework (Visual Basic, Managed C++, C#, …);

Trenz Electronic TE_USB_FX2_CyUSB.dll for .NET Framework:

• is a dynamic library;
• has only one version for both Microsoft Windows 32 and 64 bit;
• is not a COM (Component Object Model) object, so it cannot be called by C++ or Python code;
• is a managed Microsoft .NET class library that can be used with any programming language of the .NET Framework (Visual Basic, Managed C++, C#, …);
• is open source (can be modified and extended).

Advantage:

• Possible to directly access CyUSB.dll classes and functions to extend Trenz Electronic TE_USB_FX2_CyUSB.dll libraries with other classes and functions (for example Plug and play functions and asynchronous multithread bulk data trasfers)
• Support of multi-thread and multi-process programming.
• It is a managed Microsoft .NET class library that can be used with all languages of the NET Framework (Visual Basic, Managed C++, C#, …) or other .NET infrastructures (such as IronPython).

Disadvantage:

• TE_USB_FX2_CyUSB.dll has no binding to Python because it is pure .NET CLR code that cannot be compiled as a COM object.  If the user application is mainly made of C# code, it is convenient to use IronPython.If the user application is mainly made of Python, it is convenient to use Python for .NET package.

Differences Between TE_USB_FX2_CyAPI (C++) APIs and TE_USB_FX2_CyUSB (.NET) API

TE_USB_FX2_CyAPI (C++) APIs and TE_USB_FX2_CyUSB (.NET) API do not have the same signature although they are very similar. The signature of the pure extern C code library version of TE_USB_FX2_CyAPI APIs available for developers (codename: simplified TE_USB_FX2_CyAPI APIs) is slightly different from the two signatures above.
TE_USB_FX2_CyUSB (.NET) API is intrinsically cleaner than TE_USB_FX2_CyAPI (C++) APIs because CyUSB.dll is intrinsically cleaner than CyAPI.lib.
Please note that CCyUSBDevice Cypress class in the Cypress CyAPI C++ API is actually the list of all USB devices currently served by a Cypress USB driver derivative (e.g. Cypress generic USB device or Trenz Electronic USB FX2 device). For ease of understanding and convenience, Trenz Electronic named the corresponding variable as USBdevList.

Most functions, parameters and variables have maintained name and meaning across APIs. A notable exceptions is recalled in the following table.

Possible Future Work

A pure extern C code library version of TE_USB_FX2_CyAPI (C++) APIs and TE_USB_FX2_CyUSB (.NET) API would

• ease binding from Python or another programming language, but also
• make impossible to directly access CyAPI.lib classes and functions to extend Trenz Electronic TE_USB_FX2_CyAPI.dll libraries or CyUSB.lib classes and methods to extend Trenz Electronic TE_USB_FX2_CyUSB.dll library.

At this moment a simplified TE_USB_FX2_CyAPI (C++) API is used with Open_FUT (gen3) tool but it is not thread safe.

Libusb and libusbx libraries

For Windows, see section "WinUSB driver and Zadig (Generation2, Generation 3, Cypress default and/or custom firmware)" of  Device Driver Layer.

For Linux, see Linux_FUT.

For Mac OS X, see "AN74505 - EZ-USB® FX2LP™ - Developing USB Application on MAC OS X using LIBUSB".