[maemo-developers] Unable to write to the serial port /dev/ttyS0 using QextSerialPort on Maemo device

[From: Suyash.Kumar at tieto.com]

OK, I understood, Thanks for the explanation Denis but I have one more question? 
IWe decided this approach as we have already implemented serial communication of Nokia N95 and PC (connected via USB cable). We simply used the symbian APIs for writing the information to the COM1 port and received the same on the windows PC's COM1 port and read it from there thus establishing a successful serial communication.

That's why I was trying the same for Maemo. The serial port is not visible physically on N95 also but somehow we managed the serial communication between device and PC using this approach.

Also, if the serial communication is not possible in this way, can you suggest me some other way/ sample code to achieve the same.

Regards,
Suyash.

-----Original Message-----
From: Rémi Denis-Courmont [mailto:remi.denis-courmont at nokia.com] 
Sent: Friday, July 02, 2010 4:44 PM
To: Kumar Suyash
Subject: Re: Unable to write to the serial port /dev/ttyS0 using QextSerialPort on Maemo device

On Friday 02 July 2010 12:10:11 ext Suyash.Kumar at tieto.com, you wrote:
> Hi Denis,
> 
> Could not understand what you meant by:
> <<Unless you have your Maemo device on a development jig, your device does
> not have a serial port.

Where do you see a serial port on the N900?
...
Nowhere?

There _is_ actually a serial port. It is muxed on some of the electrical pins 
(gold colored dots) that you can see if you remove the battery from its 
compartment.

> I am testing my application on the N900 device itself.
> Also, the command "ls -l /dev/ttyS0" gives proper output when run on the
> device terminal.

You would need to wire the above mentioned pins to see the output from ttyS0.

-- 
Rémi Denis-Courmont
Nokia Devices R&D, Maemo Software, Helsinki


On Friday 02 July 2010 10:15:25 ext Suyash.Kumar at tieto.com, you wrote:
> Hi,
> 
> I am writing a simple Qt on Maemo application for serial communication 
> between device and PC for which I am using QextSerialPort 1.2 library 
> to write on the /dev/ttyS0 port so that it could be read by the COM1 
> port on my windows machine connected to the device via USB cable.

You do realize that /dev/ttyS0 is the device for a physical serial port on Linux. Unless you have your Maemo device on a development jig, your device does not have a serial port. So no wonder that it is not working.

--
Rémi Denis-Courmont
Nokia Devices R&D, Maemo Software, Helsinki