The .NET Micro Framework (NETMF) is an Open Source .NET platform for resource-constrained devices with at least 256 KBytes of flash and 64 KBytes of RAM. It includes a small version of the .NET CLR and supports development in C#, Visual Basic .NET, and debugging (in an emulator or on hardware) using Microsoft Visual Studio. It also features a subset of the .NET base class libraries (about 70 classes with about 420 methods), a GUI framework loosely based on Windows Presentation Foundation (WPF), and additional libraries specific to embedded applications.

The .NET Micro Framework aims to make embedded development easier, faster, and less expensive by giving embedded developers access to the modern technologies and tools used by desktop application developers. Additionally, it allows desktop .NET developers to use their skills in the embedded world, enlarging the pool of qualified embedded developers.

Features

The unique features of the .NET Micro Framework (relative to other .NET platforms) are:

• A memory footprint of about 300 KB; for comparison, the next smallest .NET implementation, the .NET Compact Framework running on Windows CE, needs about 12 MB
• Can run directly "on the metal" without an operating system; running on an OS is also possible
• Supports common embedded peripherals and interconnects, including flash memory, EEPROM, GPIO, I2C, SPI, USB
• Optimized for energy-efficiency in battery-powered devices
• Does not require a memory management unit
• Provides multithreading support even when running on single-threaded operating systems
• A hardware abstraction layer allows porting to additional architectures
• A managed device driver model allows drivers for many devices to be written in C#
• Execution constraints to catch device lockups and crashes
• Transparent support for storing objects in non-volatile memory

Due to the constraints under which it operates, the .NET Micro Framework does have some limitations beyond those imposed by its slimmed-down libraries. For example, the platform does not support symmetric multi-processing, multi-dimensional arrays, machine-dependent types, or unsafe instructions. The CLR is an interpreter rather than a just-in-time compiler, and uses a simpler mark-and-sweep garbage collector rather than a generational approach. Interoperation between managed and native code currently has a number of limitations. The .NET Micro Framework does not support any .NET languages other than C# and Visual Basic ^[1] at this time.

Support

The .NET Micro Framework is currently supported on ARM architecture processors (including ARM7 and ARM9) and on Analog Devices Blackfin. The Porting Kit is now available along with the source code as a free download under the Apache 2.0 license at the Microsoft Download Center..

The .NET Micro Framework has its roots in Microsoft's SPOT initiative and was used in MSN Direct products such as smart watches before being made available to third-party developers early in 2007. It is a common platform for Windows SideShow devices and has seen adoption in other markets, such as energy management, healthcare, industrial automation, and sensor networks.

Microsoft allows developers to create applications using the .NET Micro Framework without charge, and makes an SDK available for free download that can be used with all version of Visual Studio, including the free Express editions.^[2]

In November 2009, Microsoft released the source code of the framework to the development community under the Apache 2.0 license.

In January 2010, Microsoft launched a community development site to coordinate the ongoing development of the core implementation with the open source community.^[3]

Versions

Open source

On 16 November 2009, Microsoft announced they would make the source for the .NET Micro Framework 4.0 available under the Apache License 2.0.^[4]

On 9 January 2010, GHI Electronics announced FEZ Domino, the first member of the product line called FEZ (Freakin' Easy!), a combination of open source hardware with a proprietary closed-source version of .NET Micro Framework.^[5]

On 3 August 2010, Secret Labs announced the Netduino, the first 100% open source electronics platform using the .NET Micro Framework.^[6]

In February 2011, Novell posted a preview of the Mono 2.12 C# compiler, the first open source compiler for .NET Micro Framework.^[7]

.NET Micro Framework 4.2

.NET Micro Framework 4.2 is the currently stable version,^[8] and was released August 29, 2011.

Hardware

Multiple vendors make chips, development kits and more that run .NET Micro Framework.^[9]

Netduino by Secret Labs

Netduino is an open source electronics platform using the .NET Micro Framework.^[10]

GHI Electronics

GHI Electronics makes several modules that support the .NET Micro Framework.

• EMX Module.^[11]
• ChipworkX Module^[12]
• USBizi144 Chipset^[13] and USBizi100, whose only difference is the lack of USB host support in the USBizi100^[14]

GHI also makes the ".NET FEZ" line of very small open source hardware boards with proprietary firmware, targeted for beginners. They are based on the USBizi chipset and all its features. The FEZ Domino board offers USB host. Even though FEZ is targeted for beginners, it's also a low-cost starting point for professionals wanting to explore NETMF (.NET Micro Framework).^[15] Some of these boards are physically compatible with the Arduino.

netmfdevices

Netmfdevices is an open source electronics platform using FEZHacker and .NET Micro Framework.^[16]

See also

	Free software portal
	Microsoft portal

• DirectBand
• .NET Compact Framework
• .NET Framework

References

External links

• .NET Micro Framework official site
• Open source code snippets and drivers