说明：  Keil C51标准C编译器为8051微控制器的软件开发提供了C语言环境，同时保留了汇编代码高效、快速的特点。C51已被完全集成到μVision2的集成开发环境中，这个集成开发环境包含编译器、汇编器、实时操作系统、项目管理器和调试器
(Keil C51 standard C compiler for 8051 microcontroller software development provides a C language environment, while retaining the assembly code efficient and rapid. C51 has been completely integrated into the μVision2 integrated development environment, this integrated development environment contains the compiler, assembler, real-time operating system, project management and debuggers)