Why does the MCU use the C language? The superiority of the C language

Single chip microcomputer STM32L151CCU6

1206RGB (single)

SHTF27111500%C

The transition from C to MCU, commonly referred to as single-chip microcontrollers, began in the mid to late 1980s. Objectively speaking, porting C to the 8051 MCU presented many challenges. For instance:

· The 8051 uses a non-von Neumann architecture, which separates program and data memory spaces, along with a larger on-chip addressing range;

· On-chip data and program memory are limited, but they can be extended off-chip if needed;

· On-chip peripherals have special function registers (SFRs), which don’t use the usual I/O address space;

· The 8051 has numerous derivative models—up to hundreds—which require C to handle each hardware resource without exception.

These limitations were not part of traditional C programming for MPUs. After years of effort by companies like Keil, Franklin, Archmeades, IAR, BSO/Tasking, the C language matured in the 1990s and became the standard high-level language for MCUs. The long-held belief that “high-level languages produce too large code and run too slowly for single-chip microcomputers” has been largely overcome. Today, the code size for C on the 8051 is only 1.2 to 1.5 times that of assembly, and it can easily support programs over 4K bytes. As for execution speed, using a good simulator to identify critical sections and manually optimizing them can achieve excellent performance.

In terms of development speed, software quality, structured design, and reliability, C language far surpasses assembly programming. It's now time for MCU developers to embrace the power of C.

Here are some key advantages of using C for 8051-based microcontrollers:

· You don't need to know the instruction set of the microcontroller to write a well-structured program;

· You don't need to understand the specific hardware of the MCU to create professional-level code;

· Efficient use of limited RAM through optimized data handling;

· Robust programs that prevent data corruption, ensuring stable operation;

· C provides complex data types such as arrays, structures, unions, enums, and pointers, significantly increasing flexibility and processing power;

· Supports various storage types like auto, static, const, and specific memory types for 8051 (data, idata, pdata, xdata, code), with automatic address assignment;

· Offers different compilation modes (small, compact, large) to match on-chip memory sizes;

· Handles interrupt service routines, vector tables, and on-chip protection automatically;

· Provides a rich standard library for quick access;

· Uses header files with macros, complex data definitions, and function prototypes to improve portability and support product line development;

· Strict syntax checking reduces errors and allows fast debugging at the high-level language stage;

· Easily integrates with various utilities, such as automatic initialization of on-chip resources or real-time multitasking systems, simplifying user programming and improving system safety.