Memory Access

[Moissenjeff]

Hi all

Here is my problem:

I need to write a program that reads data from the Com Port (USB) and make the data that is read accessible to another application via RAM, I could use a normal file, but that is to slow, and this requires realtime streaming.

I suspect that it requires a pointer of some sort, but I have no idea how to create a pointer that is visible for all other applications.

I will also need to make a test application that reads the data from memory to validate that it works properly

Please answer in C#, C++ or C

 

[JurkMonkey]

You can either pass an instance of your class or provide a service.

I would be tempted to provide a service much like a GPS Antenna that just spews out the data or provides classes with change notification. The observer pattern does very well in this instance.

http://www.ubuntu.com/

 

[Moissenjeff]

That does not help me. I do not know how to code it

Services, processes and the like is actually a bit above my head

 

[chigley]

You cannot use the Microsoft .NET Framework classes to directly access other types of ports, such as parallel ports or USB ports.

Any variable you declare is "in memory" so that answers that. I guess you would need to use c++ and the ddk to achieve this. Basically you would need to write your own driver. This is quite heavy and not really suitable for a C# forum. I would try reposting in the C++ forum.

 

[whosrdaddy]

maybe something like this??

http://www.codeproject.com/KB/threads/dotnetnamedpipespart1.aspx

/Daddy

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[chigley]

Not really covering the whole, "You cannot use the Microsoft .NET Framework classes to directly access other types of ports, such as parallel ports or USB ports." problem for me I'm afraid. Nice link on sharing data between apps though.

This is still a ddk issue methinks.

Charlie Benger-Stevenson
Hart Hill IT Ltd

http://www.harthill-it.co.uk

 

[JurkMonkey]

I think MS provides a ddk that is easier to use than a C++ ddk. Normally in C++ it's the equivalent of writing to a file or any data stream. I am under the impression that MS provides a class based DDK that wrap ports much like the SerialPort class for USB.

I'd be tempted to say .Net Native.

http://www.ubuntu.com/

 

[chigley]

>I'd be tempted to say .Net Native.

Can you provide us with a link to this?

If not its better that you don't post.

Charlie Benger-Stevenson
Hart Hill IT Ltd

http://www.harthill-it.co.uk

 

[JurkMonkey]

chingley - keep it up buddy. You know best.

http://www.ubuntu.com/

 

[phinoppix]

Haven't used this but i'm posting anyway:

http://www.icsharpcode.net/OpenSource/SharpUSBLib/default.aspx

After you're done with your USB reader app, try googling on inter process communication. You'll find several ways how to share data with other apps (e.g. named pipes, MMF, message registers) using managed code.

$0.02 =)

 

[Moissenjeff]

Thanx guys for your answers

I did however discover that the CAN converter dongle comes with a library file (dll) to enable read access to the stream coming through the USB port, but services/processes is still relevant to the task at hand so I thank you for getting me on the right track

Laters