Arduino making decision according to a packet received from serial port

问题

The program listen to messages from serial port in the form or where first character (A or D) means analog or digital, the 2nd character - pin, the 3rd character - 1/0 or from 0 to 255. The markers < and > show the beginning and the end of packet.

For example, if packet is received, the light is turned on by digitalWrite(13,1) But nothing happens. When I send via serial monitor, for instance: light is supposed to blink but it does not. The same with analogue outputs.

bool started = false;
bool ended = false;
char inData[5];
byte index;


void setup() 
{
  Serial.begin(9600);
}

void loop() 
{
  while (Serial.available() > 0)
  {
    char inChar = Serial.read();


    if (inChar == '<')
    {
      index = 0;
      started = true;
      ended = false; 
    }

    else if (inChar == '>')
    {
      ended = true;
      break;
    }

    else
    {
      if (index <= 4)
      {
        inData[index] = inChar;
        index++;
      }
    }



     if (started && ended)
    {
      if (inData[0] == 'A')
      {
        pinMode(inData[2],OUTPUT);
        analogWrite(inData[2],inData[4]);
      }


      else if (inData[0] == 'D')
      {
        if (inData[4] == 1)
        {
          pinMode(inData[2],OUTPUT);
          digitalWrite(inData[2],HIGH);
        }

        else if (inData[4] == 0)
        {
           pinMode(inData[2],OUTPUT);
           digitalWrite(inData[2],LOW);
        }
      }
      started = false;
      ended = false;
      index = 0; 
    }

  }


Serial.println("Sending");  



}

回答1:

The following code will allow you to execute a method with an example serial string:

<power,led>

Once it processes this string, it'll execute the following method:

sendCommand(cmd, val);

See below for an example of how to turn on an LED on PIN 11.

#include <avr/pgmspace.h>

int IRledPin = 11;

#define SOP '<'
#define EOP '>'

bool started = false;
bool ended = false;

char inData[80];
byte index;

void setup() {
  pinMode(IRledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // Read all serial data available, as fast as possible
  while (Serial.available() > 0) {
    char inChar = Serial.read();

    if (inChar == SOP) {
       index = 0;
       inData[index] = '\0';
       started = true;
       ended = false;
    } else if (inChar == EOP) {
       ended = true;
       break;
    } else {
      if (index < 79) {
        inData[index] = inChar;
        index++;
        inData[index] = '\0';
      }
    }
  }

  // We are here either because all pending serial
  // data has been read OR because an end of
  // packet marker arrived. Which is it?
  if (started && ended) {
    // The end of packet marker arrived. Process the packet
    char *cmd = strtok(inData, ",");

    if (cmd) {
       char *val = strtok(NULL, ",");
       if (val) {
          sendCommand(cmd, val);
       }
    }

    // Reset for the next packet
    started = false;
    ended = false;
    index = 0;
    inData[index] = '\0';
  }
}

void sendCommand(char *command, char *value) {
  if (strcmp(command,"power") == 0) {
    power(value);
  }
}

void power(char* value) {
  if (strcmp(value, "led") == 0) {
    digitalWrite(IRledPin, HIGH);
  }
}

回答2:

If the 2nd character is the pin, then you want inData[1] for your pin numbers instead of inData[2].

回答3:

Why do you go from inData[0] to inData[2]? Wouldn't the second character be in inData[1]?
You're setting the pinMode to the actual value of inData[2]. That means to turn on pin 13, you need to send a carriage return character ('\r').

回答4:

The code doesn't run below but it should help you to sort out your problem.

What it tries to do is split the inData into the Tokens[] array.

It then turns the ASCII data into integers with the atoi() statement.

Hope it helps.

Got the splitter from Segmentation Fault when using strtok_r

bool started = false;
bool ended = false;
char inData[5];
byte index;


void setup() 
{
  Serial.begin(9600);
}

void loop() 
{
  while (Serial.available() > 0)
  {
    char inChar = Serial.read();


    if (inChar == '<')
    {
      index = 0;
      started = true;
      ended = false; 
    }

    else if (inChar == '>')
    {
      ended = true;
      break;
    }

    else
    {
      inData[index] = inChar;
      index++;
    }


     if (started && ended)
    {

// https://stackoverflow.com/questions/2227198/segmentation-fault-when-using-strtok-r
// Splint up input data
    char *p = inData;
    char *tokens[50];
    int i = 0;

    while (i < 50) {
      tokens[i] = strtok_r(p, ",", &p);
      if (tokens[i] == NULL) {
         break;
         }
      i++;
    }

    if (tokens[0] == '<A')
      {
        pinMode(tokens[1],OUTPUT);
        analogWrite(tokens[2],tokens[3]);
      }


      else if (token[0] == '<D')
      {
        if (atoi(token[3]) == 1)
        {
          pinMode(atoi(token[1]),OUTPUT);
          digitalWrite(atoi(token[1]),HIGH);
        }

        else if (atoi(tokens[3]) == 0)
        {
           pinMode(atoi(tokens[1]),OUTPUT);
           digitalWrite(atoi(tokens[1]),LOW);
        }
      }
      started = false;
      ended = false;
      index = 0; 
    }

  }

来源：https://stackoverflow.com/questions/9012819/arduino-making-decision-according-to-a-packet-received-from-serial-port

标签

arduino