Usin Com Ports in Windos XP for MS-DOS apps

[ggarciac]

Hi all,

I beg your assistance with some (i think) common problem when proramming devices through serial port.

Equipment:
Modern Laptop (Pentium 4 3.0ghz)
Windows XP
No serial ports. USB-to-Serial lead

Problem:
I have to program devices with an old MS-DOS software which has no Windows version (and it seems it will never have one). Trying with clock emulation and other WinXP compatibility options for .PIF files, i managed the program to "recognize" a serial port, but when trying to read through it, it seems to loss the link.

As far as i know, there could be 2 problems. WinXP prevents software to access serial port directly (but software finally "sees" the com port), and/or software can't keep connection stable due to the speed of the laptop, even if you enable the "emulate compatible hardware clock" option.

Any suggestions?

Thank you in advance.

 

[zeitghost]

If it's a dos app, it probably accesses the hardware direct.

How it does that at the end of a usb link is beyond my capactity to imagine.

Plus XP will not allow direct hardware access.

NT was bad enough, but it did sort of work, albeit slowly, with dos serial apps.

rgds
Zeit.

 

[muklin]

buy an old 486 and load dos on it would be cheaper and easier, If you can still handle that slo a speed. they give 486's and p166's away these days.

Serial in XP is a headache

 

[kkoorndyk]

I have developed various serial applications in C, using a BCC compiler on a Windows XP machine. I used my laptop (Sony Vaio, Athalon 4 1.0GHz) and ran the apps from the command line. My laptop has a serial port, so I have not tried serial programming for USB yet, but I have found a good source of driver development is the MSDN Library.

http://msdn.microsoft.com/library/d...eddk/html/wceddksample_serial_port_driver.asp

 

[zeitghost]

Hi, kkoorndyk.

Do your applications access the registers in the UART directly with i/o instructions?

When I was programming in a dos box on NT, I found that it did work though very very slowly, a 500MHz Pentium was slower than a 20MHz 386 under DOS.

I assume this is due to the instructions slowly permeating the protection rings of the op sys.

Anyone know any different?

rgds
Zeit.