Parity Error Under Linux

[ergousha]

I am using this simple code to send a byte through serialport. And I watch the result with a logic analyser hardware. As it seems below, same code produces expected correct result under Windows, but it gives a parity error under Linux (Raspberry Pi)
I intended to use 'even' parity which is apparently the problem. Windows version interprets correct, but Linux version fails and using default value 'none'.
When I use parity default value 'none' I got same result for both Windows and Linux.

var sp = new SerialPort('/dev/ttyAMA0', {
baudRate: 19200,
dataBits: 8,
parity: 'even',
stopBits: 1,
flowControl: false
});

var serialBuffer = new Buffer([0x01]);
sp.write(serialBuffer);

[JayBeavers]

Do you have a suggested patch?

What is the hardware environment you're using to monitor? Looks like you're using a protocol analyzer?

[ergousha]

Yes, I hardwired to computer's serial port and I am using a protocol analyzer. I am pretty sure about the result. I am electronics engineer using such measurement tools long time. http://www.saleae.com/logic
I looked at source code and I saw there are two versions for Windows and Unix. (serialport_unix.cpp and serialport_win.cpp) First I suspected that 'even' parameter is interpreted wrong by unix code. There is a switch statement. But I do not have IDE to debug.
serialport_unix.cpp line 163:
switch (data->parity)
{
case SERIALPORT_PARITY_NONE:

I have also looked at tests included in source. They use parity 'none'. I think echo test will fail when 'even' parameter is selected.

[joshmh]

This should fix it: #220

[voodootikigod]

Can you verify this with the latest 1.2.1 release?

[ergousha]

I have got some unexpected results at first sight. I will share my feedback after further investigation.

[ergousha]

Please find my latest test results below. This is latest version 1.2.2

I matched Windows version with Linux version. Windows version produces all results correctly. It looks like setting parity has effect on databits.

Before releasing a new version, if you need me to test, I would gladly contribute to the project.

[voodootikigod]

@ergousha how did you generate those graphs?

[ergousha]

Results measured with logic analyser hardware connected to computer's serial port. Then this measurements interpereted when I enter expected parameters, so it tries data to split into frames and shows errors.
I am pretty sure about results. If you wish to see the process, I can record a video too..
Why I thought to use analyser, because I had an application working on Windows, when I ported it to Linux it did not worked. I looked into communication signals and I saw parity creates error.

[robinxc]

yes i find this bug last year.
you could alter the serialport_unix.cpp
switch (data->parity....

[voodootikigod]

We are aware of the issue, we are working on a fix that doesn't break
everything else. Someone proposed a change, but much like @qindl
suggestion, but it broke many other things. Working on it.

On Thu, Oct 31, 2013 at 10:49 AM, qindl [email protected] wrote:

yes i find this bug last year.
you could alter the serialport_unix.cpp

switch (data->parity....

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/219#issuecomment-27491967
.

Chris Williams

@voodootikigod http://twitter.com/voodootikigod |
GitHubhttp://github.com/voodootikigod

The things I make that you should check out:
SaferAging http://www.saferaging.com/ | JSConf http://jsconf.com/ |
RobotsConf http://robotsconf.com/ | RobotsWeeklyhttp://robotsweekly.com/

Help me end the negativity on the internet, share
thishttp://jsconf.eu/2011/an_end_to_negativity.html
.

[voodootikigod]

@ergousha can you try out this branch: https://github.com/voodootikigod/node-serialport/tree/databits

Thank you,

[ergousha]

The new branch gives an error at the serial port opening. (even with default opening parameters)

events.js:72
throw er; // Unhandled 'error' event
^
Error: Serialport not open.
at SerialPortFactory.SerialPort.close (/home/neo/www/node_modules/serialport/serialport.js:390:17)
at Object. (/home/neo/www/sertest.js:12:4)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:901:3

[voodootikigod]

Can you please provide the code snippet you are using? I am not seeing
similar on my side.

Thank you,

On Sun, Nov 3, 2013 at 4:29 AM, Ergin Akin [email protected] wrote:

The new branch gives an error at the serial port opening. (even with
default opening parameters)

events.js:72
throw er; // Unhandled 'error' event
^
Error: Serialport not open.
at SerialPortFactory.SerialPort.close
(/home/neo/www/node_modules/serialport/serialport.js:390:17)
at Object. (/home/neo/www/sertest.js:12:4)
at Module.
_compile (module.js:456:26) at Object.Module._extensions..js
(module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:901:3

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/219#issuecomment-27641346
.

Chris Williams

@voodootikigod http://twitter.com/voodootikigod |
GitHubhttp://github.com/voodootikigod

The things I make that you should check out:
SaferAging http://www.saferaging.com/ | JSConf http://jsconf.com/ |
RobotsConf http://robotsconf.com/ | RobotsWeeklyhttp://robotsweekly.com/

Help me end the negativity on the internet, share
thishttp://jsconf.eu/2011/an_end_to_negativity.html
.

[ergousha]

var serialport = require("serialport");
var serialBuffer = new Buffer([0x01, 0x02, 0x03]);

var SerialPort = serialport.SerialPort;

var sp = new SerialPort("/dev/ttyAMA0");

sp.on("open", function () {
var myVar=setInterval(function(){sp.write(serialBuffer)},1000);
});

sp.close();

Or

var serialport = require("serialport");
var serialBuffer = new Buffer([0x01, 0x02, 0x03]);

var SerialPort = serialport.SerialPort;

var sp = new SerialPort("/dev/ttyAMA0", {
baudRate: 19200,
dataBits: 8,
parity: 'none',
stopBits: 1,
flowControl: false
});

sp.on("open", function () {
var myVar=setInterval(function(){sp.write(serialBuffer)},1000);
});

sp.close();

[voodootikigod]

Move the close into the .on open callback and it will work fine

On Sunday, November 3, 2013, Ergin Akin wrote:

var serialport = require("serialport");
var serialBuffer = new Buffer([0x01, 0x02, 0x03]);

var SerialPort = serialport.SerialPort;

var sp = new SerialPort("/dev/ttyAMA0");

sp.on("open", function () {
var myVar=setInterval(function(){sp.write(serialBuffer)},1000);
});

sp.close();

Or

var serialport = require("serialport");
var serialBuffer = new Buffer([0x01, 0x02, 0x03]);

var SerialPort = serialport.SerialPort;

var sp = new SerialPort("/dev/ttyAMA0", {
baudRate: 19200,
dataBits: 8,
parity: 'none',
stopBits: 1,
flowControl: false
});

sp.on("open", function () {
var myVar=setInterval(function(){sp.write(serialBuffer)},1000);
});

sp.close();

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/219#issuecomment-27648749
.

Chris Williams

@voodootikigod http://twitter.com/voodootikigod |
GitHubhttp://github.com/voodootikigod

The things I make that you should check out:
SaferAging http://www.saferaging.com/ | JSConf http://jsconf.com/ |
RobotsConf http://robotsconf.com/ | RobotsWeeklyhttp://robotsweekly.com/

Help me end the negativity on the internet, share
thishttp://jsconf.eu/2011/an_end_to_negativity.html
.

[ergousha]

I confirm that problem is fixed 👍

Tested under Linux with 19600 baud rate.
Test parameters and results:
8N1 OK
8E1 OK
8O1 OK
7N1 OK
7E1 OK
7O1 OK

[robinxc]

parity: "even" ERROR ;could not used

log:
[root@router-cmcc tests]# node readtest.js
=>connected
writed all
/home/Router/test/serial/tests/readtest.js:1956: Uncaught ReferenceError: data is not defined

readtest.js code:

var portName = '/dev/ttyS3';
var serial_port = new SerialPort(portName, {
baudRate: 2400,
dataBits: 8,
parity: "even",
stopBits: 1,
flowControl: false
});
var buf5 = new Buffer(8);
buf5[0] = "0x1"
buf5[1] = "0x03"
buf5[2] = "0x00"
buf5[3] = "0x26"
buf5[4] = "0x00"
buf5[5] = "0x3"
buf5[6] = "0xe4"
buf5[7] = "0x0"

serial_port.on("open", function () {
console.log('connected');
serial_port.write(buf5);
console.log('writed all');
})

serial_port.on("data", function (data) {
console.log('data received: ' + data);
for(var i=0;i<data.length;i++){
console.log('-'+ data.slice(i,i+1).toString('hex').toUpperCase());
}
//util.puts("here: "+data);
})

serial_port.on("error", function (msg) {
util.puts("error: "+msg);
})
repl.start("=>")

[voodootikigod]

Merged in. @robinxc looks like an error in your code.

[robinxc]

what error? show me :)

[ergousha]

My declared problem solved by databits branch.