Nodejs Serialport not open after 1012 writes

Question

I'm using nodejs "v0.10.28" and npm "1.4.9", downloaded from http://nodejs.org.

I've installed serialport through npm

npm install serialport

My program is running on a Raspberry-pi and needs to keep sending updated values quickly through serialport, so I've created this test program.

var serialPort = require("serialport");
var SerialPort = require("serialport").SerialPort;

var sp = new SerialPort("/dev/ttyAMA0", {
      baudrate: 9600
}, false);

console.log("Starting up serial host...");

var message = "Num: ";
var counter = 1000000;
function write()
{
        message= counter.toString();
        counter+=1;
        sp.open(function(err)
        {
                console.log("Writing serial data: " + message);
                sp.write(message, function(err, res)
                {
                        if (err)
                        {
                                console.log(err);
                        }
                        sp.close();
                });
        });
}

setTimeout(write, 10); //wait 10 ms for everything to initialize correctly
setInterval(write, 50); //write data every 50 ms

The program runs ok for exactly 1012 writes, then crashes.

Program output towards the end:

...
Writing serial data: 1001011
Writing serial data: 1001012
Writing serial data: 1001013
[Error: Serialport not open.]

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: Serialport not open.
    at SerialPortFactory.SerialPort.close (/home/pi/node_modules/serialport/serialport.js:476:17)
    at /home/pi/serialTest.js:25:7
    at SerialPortFactory.SerialPort.write (/home/pi/node_modules/serialport/serialport.js:290:9)
    at /home/pi/serialTest.js:19:13
    at /home/pi/node_modules/serialport/serialport.js:224:11

Why is it crashing? Is there any buffer overflow in memory somewhere? And why exactly 1012 writes? Very close to 1024, is it a coincidence?

Answer 1

A friend just helped with answering this privately so I'll share findings here.

Code:

var SerialPort = require("serialport").SerialPort;

var sp = new SerialPort("/dev/ttyAMA0", {
      baudrate: 9600
}, false);

console.log("Starting up serial host...");

var message = "Num: ";
var counter = 1000000;

sp.open(function(err) {
    if (err) {
        console.log("Port open error: ", err);
    }
    else {
        console.log("Port opened!");
    }
});

function write()
{

        if (sp.isOpen())  {
            message= counter.toString();
            counter+=1;

            console.log("Writing serial data: " + message);
            sp.write(message, function(err, res)
            {
                    if (err)
                    {
                            console.log(err);
                    }
                    setTimeout(write, 50);
            });
        }
        else {
            setTimeout(write, 50);
        }
}

setTimeout(write, 10); //wait 10 ms for everything to initialize correctly

If you look closely you'll notice that now sp.open() is used once and in the beginning of write function sp.isOpen() is used to check if port is open. Also setInterval(write, 50); is gone and now only use setTimeout(write, 10);

Code now works, but that still doesn't answer the question why did it use to crash when opening and closing the port in the previous code.