Author Topic: Com port access denied  (Read 9361 times)

adyble

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Com port access denied
« on: January 04, 2010, 05:40:42 pm »
Hi
I am using an nrComm and nrTerminal together, eveythying works fine.
We are receiving a constant stream with end of packet follwing the data.

However on one PC, we have the following problem :
PC has 2 on board com ports COM1, COM2

it works on Com1, then after a restart, we get "Com1 Access denied".
so we switch to Com2. it all works ok again, but after the next restart we get "com1 access denied"
and round and round it goes.

But.. if we open in hyperterminal before using our app it's ok.
Maybe the is some kind of com port reset we can perform ?

Or maybe there is some program we can use or write to see what is using the com port we can't access.

Thanks for any help

Andy

Roman Novgorodov

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Re: Com port access denied
« Reply #1 on: January 04, 2010, 06:38:08 pm »
Hello

Hmmm ... it is strange ...
It seems like serial port is busy by unknown app or system service.

What version of Windows are you using?

You can try to use PortMon tool for monitor serial port.
http://download.sysinternals.com/Files/PortMon.zip

Roman Novgorodov
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adyble

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Re: Com port access denied
« Reply #2 on: January 05, 2010, 02:23:45 pm »
I tried Portmon, but said port was in use so couldn't access it, which was strange.