Solved switching dtr and rts with turbo pascal

October 13, 2011 at 08:11:37
Specs: Windows XP
Hi, can anyone please help with code to control the DTR and CTS pins on the Com1 port. Would it be possible to latch the outputs or must one loop it to stay in the switched condition.


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October 14, 2011 at 08:51:30
✔ Best Answer
I think it is possible to control pins of COM1 port (even under XP) using Turbo Pascal since I did that years ago. I can give you a package with source code in Pascal to access and manipulate COM port; if you are interested, please contact me by a private message with your e-mail address.

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October 14, 2011 at 09:30:12
I'd be surprised if you can do that in XP. A program has to be running in supervisor mode (i.e. a device driver) to directly manipulate the hardware. I'm not aware that you can write such programs in Turbo Pascal.

Things were easier with DOS, where there was no concept of supervisor mode and user mode.

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October 14, 2011 at 11:32:51
Thanks Ivo.

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October 14, 2011 at 13:29:03

YES, you can because what you say is right but being Turbo Pascal a DOS 16 bit application the job is done by the builtin emulator NTVDM that takes care of running legacy applications and instances a "virtual" tunnel to the protected ring.

@@Johan Grobbelaar

I'll contact yo at posted address, but remove it from your post otherwise you will become a target for spammers. To contact a member of click on his/her nickname.

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