Serial.write documentation errors.

Mở tài liệu tham khảo Serial.write được liên kết và so sánh các ví dụ về tham số của tài liệu đó với hành vi một đối số được thể hiện trong sketch Processing và đầu ra Arduino. Cập nhật tài liệu tham khảo để các chữ ký được hỗ trợ và hành vi của byte ít quan trọng nhất là chính xác, sau đó xác minh rằng các ví dụ không còn cho rằng có thể gọi với nhiều tham số.

Description

1. The reference for Serial.write implies that you can have one or more parameters of type byte[], String or int. As far as I can see it accepts only one parameter (of any of those types).

The method write(int) in the type Serial is not applicable for the arguments (String, int)
The method write(int) in the type Serial is not applicable for the arguments (int, String)

2. Serial.write with integer parameter sends only the least-significant byte.

Assuming that serial.write(int-var) is valid, although not an example in Processing-4 (it was an example in Processing-3). It sends only the least-sig byte. Maybe this is as intended, but the reference doesn't say that so you'd expect the whole integer, all 4 bytes, to be written.

Expected Behavior

I'd expect the serial.write() to accept all the formats given in the reference. Assuming that the code is working correctly, then the reference should have examples of each possibility write(byte[]), byte, String, int. (I've only tested int.) No examples with multiple parameters.

I'd expect write(int) to send the whole integer, or if the help states that it only sends the least-sig byte, then 1 byte will do.

Current Behavior

Serial.write does not accept the reference multi-parameter examples.

The method write(int) in the type Serial is not applicable for the arguments (int, String)
The method write(int) in the type Serial is not applicable for the arguments (String, int)

Serial.write(int) sends only the least-sig byte.

Steps to Reproduce

Processing code.

• Comment in lines 28,29 and they are not accepted.
• Sends int to Ard at 1Hz. Prints out the returned text.) You can see that Ard is getting only the least sig-byte.

final boolean T = true;
final boolean F = false;

import processing.serial.*;

Serial port; 

byte b1;
int i1 = 0;
long l1;

void setup() {
  frameRate(10);
  size(140, 80);
  port = new Serial(this, "COM13", 9600);
  noStroke();
  smooth();
}



void draw() {
  boolean inComing = F;
  char ch;
  if (frameCount > 50 && frameCount % 10 == 0) {
    b1 = (byte) i1;
    l1 = i1;

    //port.write(i1, "");
    //port.write("", i1);    
    
    port.write(i1);
    print(String.format("X %d ",l1));
    i1 += 53;
  }
  if (port.available() > 0)  {print("R "); inComing = T; delay(10);}
  while (port.available() > 0)
  {
    ch = (char) port.read();
    print(ch);
  }
  if (inComing) {print(" "); inComing = F;}
}

Arduino Code

#define pM pinMode
#define dW digitalWrite

int i1;
int led = 7;

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

  Serial.println();
  Serial.println(__FILE__);
  Serial.println(__DATE__);
  Serial.println(__TIME__);


  pM(led, OUTPUT);
}

void loop()
{  
  dW(led, 0);
  if (Serial.available() > 0) {
    i1 = Serial.read(); 
    dW(led, 1);
    Serial.print(i1);
  }
  delay(10);
}

Output:

X 0 R 0 X 53 R 53 X 106 R 106 X 159 R 159 X 212 R 212 X 265 R 9
X 318 R 62 X 371 R 115 X 424 R 168 X 477 R 221 X 530 R 18
X 583 R 71 X 636 R 124 X 689 R 177 X 742 R 230 X 795 R 27
X 848 R 80 X 901 R 133

X is the value Processing has, continues increasing. Arduino is sending back value of only 1 byte, limited to 255.

Your Environment

Windows-10, Processing 4.0b3, Ard 1.8.5, Ard-Nano.

Possible Causes / Solutions

Which is right, the serial.write() behaviour, or the reference? Why was the documentation changed between Processing 3 and 4. The easy solution is to make the reference match the current behaviour. Only 1 parameter of 3 types.

For the write(int) add the reference line, something like "with an integer parameter the least-significant byte is sent (value 0..255).