Embedded C is a set of language extensions for the C Programming language by the C Standards committee to address commonality issues that exist between C extensions for different embedded systems. Historically, embedded C programming requires nonstandard extensions to the C language in order to support exotic features such as fixed-point arithmetic, multiple distinct memory banks, and basic I/O operations.

Embedded C Advantages

Embedded C use most of the syntax and semantics of standard C, e.g., main() function, variable definition, datatype declaration, conditional statements (if, switch. case), loops (while, for), functions, arrays and strings, structures and union, bit operations, macros, unions,etc.

• It is small and reasonably simpler to learn, understand, program and debug.
• Compared to assembly language, C Code written is more reliable and scalable, more portable between different platform.
• C Compilers are available for almost all embedded devices in use today, and there is a large pool of experienced C programmers.
• Unlike assembly, C has advantage of processor-independence and is not specific to any particular microprocessor/ microcontroller or any system. This makes it convenient for a user to develop programs that can run on most of the systems.
• As C combines functionality of assembly language and features of high level languages, C is treated as a ‘middle-level computer language’ or ‘high level assembly language’
• It is fairly efficient
• It supports access to I/O and provides ease of management of large embedded projects.

Embedded C vs Standard C

Though C and embedded C appear different and are used in different contexts, they have more similarities than the differences. Most of the constructs are same; the difference lies in their applications.

• C is used for desktop computers, while embedded C is for microcontroller based applications.
• C takes more resources of a desktop PC like memory, OS, etc while programming on desktop systems what embedded C can not. Embedded C has to use with the limited resources (RAM, ROM, I/Os) on an embedded processor. Thus, program code must fit into the available program memory. If code exceeds the limit, the system is likely to crash.
• Compilers for C (ANSI C) typically generate OS dependent executable files. Embedded C requires compilers to create files to be downloaded to the microcontrollers/microprocessors where it needs to run. Embedded compilers give access to all resources which is not provided in compilers for desktop computer applications.
• Embedded systems often have the real-time constraints, which is usually not there with desktop computer applications.
• Embedded systems often do not have a console, which is available in case of desktop applications.

SOURCE: INTERNET