Writefile COMM Port Inter character timing problem.

[GeorgeM]

I am trying to use Writefile to send data out a comm port but am having problems achieving a 3 millisecond intercharacter delay 100 percent of the time, which is required to communicate true 9600 baud. I have even tried running my comm send routine in a seperate thread with a time critical priority and it still fails to send out data with proper intercharacter timing. Everything is fine about 99 percent of the time but even when the app is running on a DELL 450 with 128 megs of ram and little running of the machine I have this problem. If there is anything you can think of that would help me correct this problem please email me at toloquta@yahoo.com

Thanks,

George McCollister

[craig strudwicke]

George,

There is a website you should check out :

www.imagination.com

They have a product called Hyperkernal which has more deterministic timing capabilities than the standard kernal. Will send you a document (real email address)

Regards

Craig Strudwicke

strud

[Kailash Marthi]

How do you set intercharacter delay ? Do you use overlapped I/O ? Do you use any external high-precision timer ?

All said and done, there is no right way to do it. Lot depends on the kernel and driver. Still we can eliminate application loop-holes if you post some code/answers to the above questions. Having a time-critical thread is a good idea. Do you also change the priority class ?

Kailash