MCU serial port interrupt and message receiving and sending processing -- judge and control the received information

Catalog

The problem of making trouble by yourself this time ：（ An experiment made by myself ）

Realization effect ：

Preliminary foundation ：

Implementation steps

experimental result ：

Main code

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The problem of making trouble by yourself this time ：（ An experiment made by myself ）

With 51 For single-chip computer , Timer 2 As a serial port 1 To conduct serial port experiments , Check the following data ( Any data )

"hello"--1

"yzh666"--2

"aqawaer"--3

Realization effect ：

After receiving these message fields, the single-chip microcomputer judges and displays the number of the message in the first position of the nixie tube , Take a look at the real-time performance of the serial port .

Preliminary foundation ：

         There are many baud rates for serial ports , The unit is bits per second , With 9600bps For example , In my submission 9600 Bitwise s, If there is no verification 8 Digit bit , A start bit and a stop bit form a data frame （ common 10 position ),

Start bit ：1
Data bits ：8
Stop bit ：1
Check bit ：0

Then every s Can accept 960 A packet , Every eight bits is a byte , That's no s Can accept 960 Bytes （ That's one char Or is it unsigned char Data of type ), Then it is equivalent to every 1.041ms Accept a character .

Serial interrupt ： Every time you send or receive data TI or RI Set as 1 An interrupt is triggered （ Hardware placement ), Therefore, software reset is required after triggering the interrupt （ Set as 0), Priority is lower than timer interrupt . Serial port interrupt is generally used to receive data .

Implementation steps

         Use an array cache to receive data , Set a flag to indicate whether there is data rf , The time interval before two data transmissions rt , Set up a 1ms A timer that generates an interrupt 1, Each timer 1 Enter interrupt judgment RI:RI by 1 be rt by 0（ It means that there are still data being accepted ）,RI by 0（ be rt Start timing , During the timing, only RI by 1 Again from 0 Start counting , Because each time the serial port accepts a data frame, it will be set by the software 0）, When rt>40 when , explain （RI by 0 And 40ms If no data is received within this period, it is judged that the data acceptance is completed , The data sent and accepted has been cleared rf ,rt） Here is 40ms I just set it up myself .

After receiving the data , use C Library function strcmp(char *src, char *dst), Add the header file of the library "string.h"

strcmp(Rbuf,"awaqaer\r\n")==0 To determine whether the corresponding data has been received

experimental result ：

I set it as 1000ms Automatically send at intervals of "hello","yzh666","awaqaer" A satisfactory result has been achieved ：

First, the serial port ：

The effect on the board ：

Judge the serial number corresponding to the three pieces of data ：

Main code

Timer 1 And serial port code

void TIME1() interrupt 3{
	
	smg_play(DT[s],s++);
	if(s>7)s=0;
	smgtime++;
	time++;
	if(rf){
		if(!RI){
				if(rt++==40){
				// It is considered that the primary data transmission is completed 
				 
				Rbuf[i]='\r';
				Rbuf[i+1]='\n';
				Rbuf[i+2]='\0';
					 
					if(strcmp(Rbuf,"yzh666\r\n")==0)DT[0]=1;
					else if(strcmp(Rbuf,"hello\r\n")==0)DT[0]=2;
					else if(strcmp(Rbuf,"awaqaer\r\n")==0)DT[0]=3;
					else DT[0]=0;
					SendString(Rbuf);
						i=0;
						rf=0;
						
				}
		}
		else {
			rt=0;
		}
		
	}
}

void Uart1() interrupt 4{
	
	if(RI){
		RI=0;
		if(!rf){
			rf=1;
			Rbuf[i++]=SBUF;
			}
		else {
			
			Rbuf[i++]=SBUF;
			
		}
	}
	
	
}

There are still defects

         When the interval between sending data is 300ms There is no problem in judging the above data , But less than 300ms, I measured 200ms There are two messages that are accepted as the same message , I set RI==0 The interval is 10（ The code says 40） The same is true for the interval between messages . In my understanding ,9600 Of bps, The transmission rate is 1 Data frames /1.041ms, wait for 40 A byte of time is about the same 40ms, The running time of the program can be ignored , Serial port and timer preemption cpu And the resulting error is not big , because 1ms Yes cpu It's been a long time .