strcmp 脚本读取串行监视器失败

Question

我有一个脚本读取串行监视器并寻找“OK”响应。我能够在名为 message 的变量中捕获 OK 响应并将其打印到串行监视器，但是当我尝试在 if 语句中使用 message 变量时，它没有按预期执行。当变量 message = OK 时，下面的语句仍然给出 false。有谁知道问题出在哪里？

 if (strcmp (message,"OK") == 0) {
  Serial.println("true");
 }
 else {
  Serial.println("false");
 }

完整代码：

//#include <HardwareSerial.h>
const unsigned int MAX_MESSAGE_LENGTH = 12;

void setup() {
Serial2.begin(115200,SERIAL_8N1); //open modem serial port
Serial.println("serial ports are open");
}

void loop() {
  
 Serial2.write("AT\r\n");

 while (Serial2.available() > 0){
   //Create a place to hold the incoming message
   static char message[MAX_MESSAGE_LENGTH];
   static unsigned int message_pos = 0;
   
   //Read the next available byte in the serial receive buffer
   char inByte = Serial2.read();
   
   //Message coming in (check not terminating character) and guard for over message size
   if ( inByte != '\n' && (message_pos < MAX_MESSAGE_LENGTH - 1) )
   {
     //Add the incoming byte to our message
     message[message_pos] = inByte;
     message_pos++;
   }
   
   //Full message received...
   else
   {
     //Add null character to string
     message[message_pos] = '[=11=]';
        //Print the message (or do other things)
     Serial.println("loop");
     delay(100);
     Serial.println(message);
     //Reset for the next message
      message_pos = 0;
     
     if (strcmp (message,"OK") == 0) {
      Serial.println("true");
     }
     else {
      Serial.println("false");
     }
   }
      
 }
delay(5000);
}

串行监视器如下所示：

22:11:51.970 -> serial ports are open
22:12:16.984 -> loop
22:12:17.078 -> AT


22:12:17.078 -> false
22:12:17.078 -> loop
22:12:17.171 -> OK

22:12:17.171 -> false
22:12:17.171 -> loop
22:12:17.266 -> AT


22:12:17.266 -> false
22:12:17.266 -> loop
22:12:17.360 -> OK

22:12:17.360 -> false

Answer 1

收到的回复是 "OK\r\n"，所以实际消息是 "OK\r"。如果您临时打印每个接收到的字符，它有助于调试。

要忽略命令的回显，为其插入另一个 strcmp() 并做出相应的反应，例如什么都不做。

strcmp 脚本读取串行监视器失败

strcmp script reading serial monitor failing

c

string

character

serial-monitor