单片机汇编延时计算小程序（Singlechip assembly delay calculation applet）.docVIP

单片机汇编延时计算小程序（Singlechip assembly delay calculation applet） Recently, when you do SCM process, you need a number of more precise delay. The C language is not easy to make, and I use the STC microcontroller, each instruction and 51 compared to the time spent in different. Finally decided to use C language embedded assembly method to solve. The embedded assembly code block is as follows: #pragma ASM MOV, R6, #X DELAY2:, MOV, R7, #Y DELAY1:, DJNZ, R7, DELAY1 DJNZ, R6, DELAY2 RET #pragma endasm Among them, the number of MOV, DJNZ, RET machine cycle instruction takes in the 51 SCM can be found, and I use this STC microcontroller, spent the three instructions time just were 51 1/6. In this way, we can calculate the delay procedure in 51 single end delay long before and after divided by 6, is the STC MCU delay length (not that all STC microcontroller are applicable, please refer to you using STC microcontroller specific types of manual, see the three instructions is 6 times faster than 51). In the 51 single-chip microcomputer, the number of machine cycles spent in the above assembly program is: 1+X* (1+2*Y+2) +2 = 3+ (2Y+3) X In this way, the delay time can be obtained only by adjusting the value of X and Y and combining the specific crystal frequency. But if I want to delay the time of T us, how can I determine X and Y? Of course, you can first plug in a X, and then calculate the T according to Y. However, that does not guarantee that the selected X and Y errors are minimal or small. So, Im going to write a program to calculate the optimal values for X and Y. Here is the source code of the program: /************************************************** Compilation delay calculation gadget Support 51 single-chip microcomputer and part of STC microcontroller **************************************************/ #includestdio.h #includemath.h Unsigned char mcu_type=0; / / single species Float f=0; / / crystal frequency Float delay_time=0; / / delay time Unsigned int w=0; / / the c