c语言在单片机中的应用（Application of C language in single chip microcomputer）.doc

c语言在单片机中的应用（Application of C language in single chip microcomputer） C language in the development of single-chip application time: 2011-05-21 22:30:57 source: the author: in the development and application of SCM, has gradually begun to introduce high-level language, C is one of them. For those who are used to the compilation, they always feel that the high-level language controllability is not good, so it is better than the assembly. But as long as we master a certain C language knowledge, some things still easy to do, the following is the author of several problems encountered in practical work, I hope for beginners C51 who will help. First, the preparation of C51 hot boot code For industrial control computers, there is usually a watchdog circuit that acts as a watchdog and resets the computer, which is called hot start. Thermal startup is generally not allowed to start from scratch, which will cause the existing measured or calculated values to reset, resulting in system work anomalies. As a result, when the program must judge whether it is hot or cold start, the usual method is to identify a memory unit as a flag bit (such as 0x7F bits and 0x7e bits), When you start, you read the contents of the memory cell first, and if it is equal to a particular value (for example, two memory cells are 0XAA), it is considered a hot boot, It is a cold start, the execution of the program initialization part, and 0XAA to the two memory unit. According to the above design idea, when programming, set a pointer, so that it points to a specific memory unit, such as 0x7F, and then in the program to determine the procedures as follows: Void, main () {char, data, *HotPoint= (char *) 0x7f; If ((*HotPoint==0xaa) (* (--HotPoint) ==0xaa)) {/ * hot start processing } Else {HotPoint=0x7e; / * cold start point *HotPoint=0xaa; * (++HotPoint) =0xaa; } Normal working code * / / * } However, the actual debugging found that, whether it is hot start or cold start, after the boot, all memory units