Middleware Libraries

Benefits of Using MDK Middleware

  • Develop robust and powerful applications fast - the CMSIS-RTOS RTX real-time operating system, together with its sources, gives you all the resources you need to create and control multi-threaded, real-time applications and can be tailored to your exact system requirements. Keil middleware uses a CMSIS-RTOS.
  • Do only what you need MDK-Plus and MDK-Professional include libraries to enable TCP/IP networking, USB Host and Device, file-system support, graphics component, and mbed components for IoT connectivity (compare editions to learn more about the individual availability of software components). Use these existing resources to allow you to focus on the development of the core of your application. There's no need to waste time re-implementing low-level functions.
  • Take advantage of ARM's expertise - all MDK Middleware libraries have been designed, tested, and optimized by ARM engineers for ARM Cortex-M platforms. The libraries have a modular design with simple APIs. Documentation and examples make it easy to re-use the work done by our experts.
  • Source Code - all middleware components are available as source code on request. This allows you to rebuild libraries or extend their feature set and is useful when source code is needed for product certification.


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Middleware Components

File System

The File System component allows your embedded applications to create, save, read, and modify files in a wide range of standard storage devices. The File System component offers:

  • Standard ANSI C File I/O application interface
  • RAM, ROM, NOR and NAND Flash support
  • SD/SDHC/MMC/eMMC Memory Card support
  • FAT12, FAT16, and FAT32 formats
  • Reentrant and thread-safe operation
  • Simultaneous access to multiple storage devices.

USB Host and Device

MDK Middleware provides USB Host and USB Device support for embedded systems. The USB Device interface uses standard device driver classes that are available with all modern operating systems. Host driver development is not required. The USB component supports ADC, CDC, HID, MSC and custom USB classes.


The Network component is a full featured networking suite optimized for ARM Cortex-M-based MCUs supporting IPv4 and IPv6 (IPv6 in MDK-Professional only). It has a small code footprint, and delivers excellent performance. The suite provides comprehensive support for transmission protocols such as TCP and UDP, as well as application level services and clients including HTTP, Telnet, SMTP, SNMP, and FTP. It provides all the features required for modern networking.

Graphical User Interface (GUI)

The GUI Library is a fully featured graphics suite that makes it possible to add graphical user interfaces to embedded applications. It supports a large number of displays and includes tools for rapid GUI creation.

  • Supports monochrome, grayscale and color LCDs
  • Drivers for many displays and display controllers included
  • Window Manager for handling multiple windows
  • Many widget-like buttons, checkboxes and icons available
  • Skinning support for a custom look and feel
  • Optimized for speed and size
  • Wide range of examples for evaluation boards.

IoT Connectivity

The middleware in MDK-Professional provides interfaces to mbed software components that enable secure communication and Internet of Things (IoT) connectivity.

  • mbed TLS adds cryptographic and SSL/TLS capabilities with a library collection optimized for embedded systems.
  • mbed Client implements the OMA Lightweight M2M protocol (from Open Mobile Alliance) and interfaces to the mbed Device Server that connects IoT devices to web applications.

Middleware Licensing

MDK Middleware is supplied royalty-free as part of MDK-Professional or MDK-Plus Edition. Each license entitles a single engineer to use the MDK Middleware libraries in multiple projects. MDK Middleware source code is available on request.


  • MDK-Professional includes MDK Middleware components for TCP/IP Networking (IPv4 and IPv6), File System, USB (Device and Host), Graphics, and mbed IoT Connectivity in binary form.
  • MDK-Plus includes MDK Middleware components for TCP/IP Networking (IPv4 only), File System, USB Device, and Graphics in binary form.
  • CMSIS-RTOS RTX Source code is included in all MDK Editions.
  • CMSIS-RTOS RTX and MDK Middleware components may only be included in your final product in object form. The license does not grant you the right to distribute the source code.


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