A method of quickly transplanting library function code to register code by single chip microcomputer

   Now more and more SCM development uses the library function version , Register versions are used less and less . However, using library functions in some projects will cause the program to run slowly , It runs faster without directly operating registers . So in the projects with strict time requirements , You still need to use registers to develop . If you can't find the register related sample code , It is difficult to develop . Today, let's summarize a method for quickly porting library functions to registers , This method is a general method , It can be used on any single chip microcomputer .

   Now use one STM8 SCM library function project to give an example .

   The main function of this code is to use the timer 1 To calculate the frequency of the input waveform . For the initialization of timers, library functions are used , Now change the library function of timer initialization part to register .

   First, single step debugging , Enter the initialization function .

   Step into this function .

   You can see that in this function 6 A register , Will this 6 Registers are added to the observation window respectively .

   In the code, registers are operated by means of pointers , So you should pay attention to the name format when adding registers to the observation window , Need to put TIM1->ARRH It is amended as follows TIM1_ARRH Format . When adding registers , You can click the mouse directly at the position of the observation window expression , Enter the name of the register directly .

   Then change the display mode of register value to 16 Base display . Right click the register in the observation window , choice 16 Base display .

   Add all other registers in the same way .

   At this time, the values of the registers are all the default values , Then step through the program . Observe the change of register value .

   After the current function is executed , All register values are the values set by the library function . Record the values of these registers .

   amount to TIM1_TimeBaseInit() The function sets these registers , Then the set register value is the value in the variable observation window . Follow the same method , Sequential single step commissioning , Record the values of all initialization registers .

   When all the register values in the initialization code are recorded , In this case, you can directly replace the library function with a register .

   Run the program after the replacement , Observe whether the running results of the program are correct . By observing the result of serial port output, it is proved that the program execution is correct .

   In this way, through the method of single step debugging , Directly observe the value of the register , You can quickly figure out which registers are set in the library function code , What is the set value . When the set register value is known , And then by looking up the information of single-chip computer , Compare the meaning of each bit in the register , You know which functions to use and which bits of which registers to set .

   After reading the register data , Understand the function of each register , At this time, you can optimize the initialization of registers , Make the code look clearer .

   Change the setting of the register to bit operation mode , In this way, you can see which bits of which register are operated directly through the code . Recompile and download after modification , Verify whether the modified code functions properly .

   Through this method, we can quickly understand the use of registers , Otherwise, just look at the relevant manual of SCM register , No focus , And some manuals are very large , Look at the back and forget the front , Very inefficient . At the same time, I don't know clearly in the process of reading , In which function should some registers be set . And through the method of single step debugging , Directly observe the register set in the library function , You can quickly understand the function of registers , You can see the data of the corresponding register when you use what function , It avoids the waste of time by simply reading materials , It also improves learning efficiency .