使用win32 apiC语言从串口读取问题

问题描述

我正在尝试使用 win32 api 和 C 语言写入和读取串行端口 (arduino)。我想向arduino发送一个数字，计算那里的平方并通过C程序读取它。但是对于下面的代码，程序要么离开循环，要么不读取传入的数据。我的 C 代码：

#include <stdio.h>
#include <windows.h>
#include <string.h>
#define BUFFER_SIZE 256
int main(){
    
    HANDLE hComm = INVALID_HANDLE_VALUE;
    
    hComm = CreateFile("\\\\.\\COM5",GENERIC_READ | GENERIC_WRITE,NULL,OPEN_EXISTING,NULL);
    
    if(hComm == INVALID_HANDLE_VALUE){
        printf("CreateFile() Failed\n");
        return -1;
    }else{
        printf("CreateFile() succeeded\n");
    }
    
    DCB dcb;
    memset(&dcb,sizeof(DCB));
    
    if(!GetCommState(hComm,&dcb)){
        printf("GetCommState() Failed\n");
        return -1;
    }
    
    printf("## PLEASE SELECT FROM THE FOLLOWING ##\n");
    printf("## MENU  :              ##\n");
    printf("(1) TURN ON LED ON ARDUINO\n");
    printf("(2) TURN OFF LED ON ARDUINO\n");
    printf("(3) FLASH ARDUINO 3 TIMES\n");
    printf("(4) SEND A NUMBER TO ARDUINO TO COmpuTE SQUARE BY ARDUINO\n");
    printf("(5) Button press counter (bonus item) **not working**\n");
    printf("(0) EXIT\n");
    
    char writeBuff[BUFFER_SIZE];
    char readBuff;
    char buff[BUFFER_SIZE];
    char intSend[6];
    int choice;
    int writtenBytes = 0;
    int allReadBytes = 0;
    int readByte = 0;
    int i = 0;
    char abc[10];
    unsigned char loop = 0;
    int a;
    int index = 0;
    
    do{
        printf("PLEASE SELECT: ");
        scanf("%d",&choice);
        
        switch(choice){
            
            case 1:
                    strcpy(writeBuff,"a");
                    
                    if(WriteFile(hComm,writeBuff,1,(LPDWORD)&writtenBytes,NULL)){
                        if(writtenBytes == 0){
                            printf("WriteFile() timed out \n");
                            return -1;
                        }
                    }else{
                        printf("WriteFile() Failed\n");
                        return -1;
                    }
                    printf("%d bytes were written\n",writtenBytes);
                    writtenBytes = 0;
                    break;
                    
            case 2:
                    strcpy(writeBuff,"b");
                    
                    if(WriteFile(hComm,writtenBytes);
                    writtenBytes = 0;
                    break;
                    
            case 3:
                    strcpy(writeBuff,"c");
                    
                    if(WriteFile(hComm,&writtenBytes,writtenBytes);
                    writtenBytes = 0;
                    break;
                    
            case 4:
                    
                printf_s("Please enter a number\n");
                scanf_s(" %s",&abc);
            
                writeBuff[0] = abc[0];
                writeBuff[1] = abc[1];
                writeBuff[2] = abc[2];

                
                WriteFile(hComm,sizeof(writeBuff),NULL);
                    
                    do{
                        ReadFile(hComm,&readBuff,sizeof(readBuff),&readByte,NULL);
                        
                        buff[loop]=readBuff;
                        ++loop;
                        
                    }while(readByte > 0);
                    --loop;
                    
                    a = index;
                    for(index = a; index < loop; ++index){
                        printf_s("%c",buff[index]);
                    }
                    
                    break;
        }
            
    }while(choice != 0);
    
    if(!CloseHandle(hComm)){
        
        printf("CloseHandle() Failed\n");
        return -1;
    }
    
    return 0;
}

使用调试器，我注意到 ReadFile 读取我从 C 程序发送的内容，而不是 arduino 发送到串行端口的内容。我还测试了用数字 12 打开 LED 灯，它可以工作，所以我确定我可以用 WriteFile 发送数据。我的arduino代码：

int i;
String value;
long sqCalc;
long karesi;


void setup() {
  Serial.begin(9600);
  pinMode(LED_BUILTIN,OUTPUT);
  digitalWrite(LED_BUILTIN,LOW);
}

void loop() {
  
  if(Serial.available() > 0){

     value = Serial.readString();
     Serial.println(value);
    
    if(value == "a"){
      digitalWrite(LED_BUILTIN,HIGH);
      Serial.println("LED is ON");
      delay(250);
    }else if(value == "b"){
      digitalWrite(LED_BUILTIN,LOW);
      Serial.println("LED is OFF");
    }else if(value == "c"){
      if(digitalRead(LED_BUILTIN) == HIGH){
        for(i=0;i<3;i++){
          digitalWrite(LED_BUILTIN,LOW);
          delay(250);
          digitalWrite(LED_BUILTIN,HIGH);
          delay(250);
        }
      }
      
      if(digitalRead(LED_BUILTIN) == LOW){
        for(i=0;i<3;i++){
          digitalWrite(LED_BUILTIN,HIGH);
          delay(250);
          digitalWrite(LED_BUILTIN,LOW);
          delay(250);
        }
      }
     }
      sqCalc = value.toInt();
      if(sqCalc > 0){
          karesi = pow(sqCalc,2);
          Serial.println(karesi,DEC);
      }
      
    }
  }

最后，使用 PuTTy 测试了 arduino 代码，效果很好。

解决方法

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