dwilches/Ardity

how to use aridity to send byte

Closed this issue · 6 comments

luoxihao commented

I want to use Unity as my host computer to send instructions to Arduino. I need to send a 16-bit instruction by dividing it into two bytes, the upper 8 bits and the lower 8 bits, and send them separately

        string sendMessage = "";
        for (int i = 0;i < 14; i++)
        {
            sendMessage += Send[i];
            //Debug.Log(Send[i] + "  DEBUG");
            //sendMessage += 'U';
        }

This is a part of my code, where Send is a char array. After this, I will call the SendSerialMessage function to send the data in Send[] to Arduino. The problem I encountered is that when the data in Send[] is greater than 63, only 63 is sent to Arduino. When the data is less than 63, the data is correct. Is there any solution for this issue

dwilches commented

Hi,

  • What type is your Send variable?
  • When you send any value from 64 to 255, is 63 arriving to the Arduino?
  • What type is the variable in the Arduino side, could you also show the relevant code on that side?
luoxihao commented

arduino side

#define FRAME_HEADER 0x55    
uint8_t fromUnity[32];
void RecUnity() {  //从unity接收数据
  uint8_t f1 = 0, f2 = 0;
  while (f1 != FRAME_HEADER && Serial.available()) {
    f1 = (uint8_t)Serial.read();
    delay(2);
  }
  f2 = (uint8_t)Serial.read();
  if (f2 != FRAME_HEADER) {
    return;
  }
  fromUnity[0] =  (uint8_t)Serial.read();
  delay(2);
  //Serial.println(fromUnity[0]);
  for(uint8_t i = 1; i < fromUnity[0]; i++){
      fromUnity[i] =  (uint8_t)Serial.read();
      delay(2);
  }
  for(int i = 0 ; i < fromUnity[0];i++)  
    Serial.println((uint8_t)fromUnity[i]);  
  softSerial.write(buf, buf[2] + 2);
}

unity side

public class communication : MonoBehaviour
{
    public SerialController serialController;
    public ushort time = 1000;
    public ushort[] angel = {0,0,0,0};

    private char[] Send = new char[64];
    private byte[] Receive = new byte[64];
    // Start is called before the first frame update
    private void Awake()
    {
        Application.targetFrameRate = 30;
    }
    void Start()
    {
       
    }

    // Update is called once per frame
    void Update()
    {
        string message = serialController.ReadSerialMessage();
        if (message == null)
            return;
        if (ReferenceEquals(message, SerialController.SERIAL_DEVICE_CONNECTED))
            Debug.Log("Connection established");
        else if (ReferenceEquals(message, SerialController.SERIAL_DEVICE_DISCONNECTED))
            Debug.Log("Connection attempt failed or disconnection detected");
        else
        {
            Receive = Encoding.ASCII.GetBytes(message);
            Debug.Log("Unity arrived: " + message);
        }
    }
    char GET_LOW_BYTE(ushort num)
    {
        return (char)(num & 0xff);
    }

    char GET_HIGH_BYTE(ushort num)
    {
        return (char)(num >> 8);
    }
    ushort BYTE_TO_HW(byte A, byte B)
    {
        return ((ushort)((ushort)A << 8 | B));
    }

    public void Send_To_Move_Drivers()
    {

        Send[0] = Send[1] = (char)0x55;
        Send[2] = (char)12;//数据长度
        Send[3] = (char)3;
        Send[4] = GET_LOW_BYTE((ushort)time);//时间
        Send[5] = GET_HIGH_BYTE((ushort)time);

        Send[6] = GET_LOW_BYTE((ushort)angel[0]);//舵机1
        Send[7] = GET_HIGH_BYTE((ushort)angel[0]);

        Send[8] = GET_LOW_BYTE((ushort)angel[1]);//舵机2
        Send[9] = GET_HIGH_BYTE((ushort)angel[1]);

        Send[10] = GET_LOW_BYTE((ushort)angel[2]);//舵机3
        Send[11] = GET_HIGH_BYTE((ushort)angel[2]);
        //Debug.Log("低八位"+Send[10]);
        //Debug.Log("高八位" + Send[11]);

        Send[12] = GET_LOW_BYTE((ushort)angel[3]);//舵机4
        Send[13] = GET_HIGH_BYTE((ushort)angel[3]);

        string sendMessage = "";
        for (int i = 0;i < 14; i++)
        {
            sendMessage += Send[i];
            //Debug.Log(Send[i] + "  DEBUG");
            //sendMessage += 'U';
        }
        char[] t= sendMessage.ToCharArray();
        for (int i = 0; i < 14; i++)
        {
                Debug.Log((int)t[i]);
        }
        
        serialController.SendSerialMessage(sendMessage);
    }
}

When I wanted to send the 16-bit integer 500, I needed to split the data into the high 8 bits and low 8 bits to send separately. The high 8 bits were 0000 0001 and the low 8 bits were 1111 0100, but when the data was sent back to the Arduino through the serial port, the high 8 bits became 0000 0001 and the low 8 bits became 0011 1111.
After further testing, I found that sending 127 is normal, but once I send 128, Arduino returns 63 to me.When I send 0000 0000 1000 0000, Arduino receives 0000 0000 0011 1111. When I send 1000 0000 0000 0000, Arduino receives 0011 1111 0000 0000.
If I use a serial debugging tool to send and receive the data mentioned above and the data returned by Arduino is correct, I am confused about this.

dwilches commented

Hi

The code is quite long to follow, but my recommendation would be:

  • check for places where the code converts between signed and unsigned types
  • use byte instead of char as much as possible, both in the Arduino and C# parts
luoxihao commented

thank you so much for help me

luoxihao commented
franklikn commented

多谢哥