Trying to receive data from a device, via the coms port.
This all works fine whilst using an overlapped structure, and a very large timeout (FFFFFFFF). When this is reduced, or the overlapped replaced by a non-overlaped, then the entire system seizes up, and the only response is to switch off pc (cold boot).
This all seems to go wrong on the ReadFile (Visual C++ 6) command.
Grateful for any hints, as my head has started to hurt, and the plaster on the walls is starting to crumble!!!!!!!!!
Dave
There is lots of info about programming the ports at www.beyondlogic.org
The only port programming I've done was in DOS BASIC (a long-long time ago).
I suspect your problem is related to your Multitasking OS (Windows?) doing stuff in the background to mess-up your timing and maybe delaying access to the port. It could be an interrupt related problem too. Although, I don't remember being required to use interrupts at all with my particular DOS BASIC application... I don't think there was anything related to IRQs in my program.
