C is a set of language extensions for the C programming language by the C standards committee to address the common problems that exist between C extensions for different embedded systems. Historically, embedded C programming requires non-standard C language extensions to support exotic features such as fixed-point arithmetic, multiple distinct memory banks, and basic I / O operations. In 2008, the C Standards Committee extended the C language to address these issues by providing a common standard for all implementations to be adhered to. It includes a number of features not available in normal C, such as fixed-point arithmetic, named address spaces, and basic I / O hardware addresses. Embedded C uses most of the C standard syntax and semantics, for example, the main () function, variable definition, data type declaration, if, switch case, loops (while , For), functions, arrays and strings, joining, bit operations, macros, etc.
Advantages
• It is small and easy to learn, understand, program and debug.
• Compared to assembly language, written C code is more reliable and scalable, more portable across platforms.
• C compilers are available for almost all embedded devices that are currently in use and there are a lot of experienced C programmers.
• Unlike the assembly, C has the 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 systems.
• As C combines the functionality of the assembly language and the characteristics of high-level languages, C is treated as a 'mid-level language' or 'high-level assembly language'.
• It is quite efficient.
• Supports I / O access and facilitates the management of large integrated projects.
• Java is also used on many embedded systems, but Java programs require Java Virtual Machine (JVM), which consumes many resources. Therefore it is not used for smaller embedded devices.
• In embedded applications it is necessary to read / write data in a given address, and in C it is easy to access and modify addresses, due to the pointers that are a language feature.
Other high-level programming languages like Pascal, FORTRAN also provide some of the advantages.
As time progressed, the use of microprocessor-specific assembly only as the programming language was reduced and the embedded systems moved to C as the embedded programming language of choice. C is the most widely used programming language for integrated processors / controllers. The assembly is also used, but mainly, to implement those parts of the code in which the precision of the time, the efficiency of the code size, etc. They are very important.
Initially C was developed by Kernighan and Ritchie to fit into the 8K space and write operating (portable) systems. Originally implemented in UNIX operating systems. As it was intended for the development of operating systems, it can manipulate memory addresses. In addition, it allowed programmers to write very compact codes. This has given it the reputation as the language of choice for hackers as well.
Because assembly language programs are processor-specific, assembler language does not offer portability between systems. To overcome this disadvantage, several high-level languages, including C, emerged. Other languages like PLM, Modula-2, Pascal, etc. They also came but could not find widespread acceptance. Among them, C was widely accepted not only for embedded systems, but also for desktop applications. Although C might have lost its luster as the primary language for general-purpose applications, it remains to have a strong strong embedded programming. Due to the wide acceptance of C in the embedded systems, several types of support tools such as compilers and cross compilers, ICE, etc. arose. All this facilitated the development of embedded systems using C.
About C Language
The C language was developed by Dennis Ritchie in 1969. It is a collection of one or more functions, and each function is a collection of statements that perform a specific task.
The C language is a mid-level language, as it supports high-level applications and low-level applications. Before we get into the details of embedded C programming, we must know about organizing the RAM.
Outstanding features of the tongue
• C language is software designed with different keywords, data types, variables, constants, etc.
• Embedded C is a generic term given to a programming language written in C, which is associated with a particular hardware architecture.
• Embedded C is an extension of the C language with some additional header files. These header files can be changed from controller to controller.
• The 8051 #include <reg51.h> microcontroller is used.
Integrated system designers must know the hardware architecture for writing programs. These programs play a prominent role in the supervision and control of external devices. They also operate and directly use the micro controller's internal architecture, such as interrupt handling, timers, serial communication and other available features.
