Com port trouble in windows

[Kasper]

I apologize if this is not directly CCS related, but here goes.

we have a project with an FTDI FT232BM USB chip, connected to a PIC.
On most computers we have tried this on, it works flawlessly, but today we had a customer who could not get it working. He had a fresh install of Windows XPsp2, and device manager reported COM1, COM2 and COM4, the last one being the USB one. The problem is that he is unable to open any of the ports. Windows reports "port is in use by another program" for all of them ( 1,2 and 4). This is testing the port straight from Hyperterminal and after a reboot. The question is, what can be using the ports, making them unavailable? Is there a program out there, which will tell us which program uses what COM ports?

Any insight would be greatly appreciated :o)

Kasper
edit:typo

[rwyoung]

Another program you might want to install is "usbview". Search the FTDI website for information. It lets you see all the USB devices attached, and how they are configuring themselves.
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

[Radix]

Thanx for the tip! Can come in handy when debugging!

[Radix]

By the way: Windows can act strange if a COM port is receiving data at startup. It somehow indentifies the device attached to the COMport as a mouse! Have this often when a GPS receiver is attached to the port.

Has stranges effects on your mouse pointer, like your computer has some kind of virus

[Ttelmah]

The 'classic' software, which can make com ports 'unavailable', is the package to handle synchronisation with the Palm device (and also in some cases MicroSoft 'ActiveSync'). They have a nasty habit of scanning ports, and if they see certain types of data patterns, 'assuming' they are meant to handle the ports. I have seen systems where these packages took over every port on the machine...
There is also another 'oddity', that can bite with the USB driver. If the devices on COM1, and COM2, are not 'real' ports, but virtual ports used by some things like IRDA drivers, the FTDI installer, can make one of the registry settings say that the USB device is on 'COM1', and another say tha the device is on 'COM4'. What then happens is that the device is not properly accessible on either address (but shows in the device manager as beng on COM4). If you manually change the port used to 'COM5', exit device manager, and then go back in and change it to 'COM4', it all starts working!. This writes the correct entries to the registry.

Best Wishes

[Ttelmah]

The 'classic' software, which can make com ports 'unavailable', is the package to handle synchronisation with the Palm device (and also in some cases MicroSoft 'ActiveSync'). They have a nasty habit of scanning ports, and if they see certain types of data patterns, 'assuming' they are meant to handle the ports. I have seen systems where these packages took over every port on the machine...
There is also another 'oddity', that can bite with the USB driver. If the devices on COM1, and COM2, are not 'real' ports, but virtual ports used by some things like IRDA drivers, the FTDI installer, can make one of the registry settings say that the USB device is on 'COM1', and another say tha the device is on 'COM4'. What then happens is that the device is not properly accessible on either address (but shows in the device manager as being on COM4). If you manually change the port used to 'COM5', exit device manager, and then go back in and change it to 'COM4', it all starts working!. This writes the correct entries to the registry.

Best Wishes

[Kasper]

Thank you all for your suggestions. I will be talking with the customer later on today, assuming he is in the office, and hopefully we can figure out what is causing this weird behaviour.

Kasper

[rwyoung]

Found an interesting program called SourceUSB which is a USB message logger / analyzer. The eval version is good for 30 days. It might be of some help.

http://www.sourcequest.com/
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!