利用反转法扫描键盘，程序简单，理解稍有难度，方便51学习者的学习。-Inversion method by scanning the keyboard, the program is simple, a little difficult to understand, easy 51 learners.

简短准确的DES算法源程序，使用51汇编，注释详尽，易懂，可直接嵌入程序中。已在某RFID产品中大量生产应用。-Brief and accurate source of the DES algorithm, the use of the 51 assembly, detailed annotations, easy to understand, can be directly embedded in the program. Mass production in a RFID products.

51单片机演奏报警声音c程序，任何单片机都可搭建，简单易懂适合初学者-51 single-chip sound alarm c procedures, any microcontroller can be built, easy to understand for beginners

Easy 51 pro v2 source program (VC), Easy 51 pro v2 source (VC)