Post by thread:[OT] USB/Serial port question

If I have a PC program that accesses a serial port. I have a PC with no serial port, but do have a USB port. Can I make the USB port into a serial port with one of those USB/serial port adaptors. The question is can I make the program send and recieve data to the USB port when no serial port is present.

On Sun, 2006-01-01 at 22:08 -0800, John Pearson wrote: > If I have a PC program that accesses a serial port. I have a PC with no serial port, but do have a USB port. Can I make the USB port into a serial port with one of those USB/serial port adaptors. The question is can I make the program send and recieve data to the USB port when no serial port is present. The answer is often yes, depending on the program. What kind of program is it? Win32? DOS? If it accesses the serial port using Win32 API functions, and doesn't rely on the timing of signals on the serial port (i.e. bit twiddling the control lines) it SHOULD work fine. They're so cheap these days, buy one and try it out. TTYL ----------------------------- Herbert's PIC Stuff: http://repatch.dyndns.org:8383/pic_stuff/

> If I have a PC program that accesses a serial port. I have a > PC with no serial port, but do have a USB port. Can I make > the USB port into a serial port with one of those USB/serial > port adaptors. The question is can I make the program send > and recieve data to the USB port when no serial port is present. Yes, that is what usb/serial converters with their VCP (virtual communication port) drivers are for. but - you must use the windows calls to access the serial port (not direct hardware access) - there will be some timing differences, which might affect what you are trying to do. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

Thanks. Forgot to ask, will I be able to wiggle the DTR and RTS lines. Timming is not an issue. ----- Original Message ----- From: "Wouter van Ooijen" <spam_OUTwouterTakeThisOuTvoti.nl> To: "'Microcontroller discussion list - Public.'" <.....piclistKILLspam@spam@mit.edu> Sent: Monday, January 02, 2006 12:25 AM Subject: RE: [OT] USB/Serial port question {Quote hidden}> > If I have a PC program that accesses a serial port. I have a > > PC with no serial port, but do have a USB port. Can I make > > the USB port into a serial port with one of those USB/serial > > port adaptors. The question is can I make the program send > > and recieve data to the USB port when no serial port is present. > > Yes, that is what usb/serial converters with their VCP (virtual > communication port) drivers are for. but > - you must use the windows calls to access the serial port (not direct > hardware access) > - there will be some timing differences, which might affect what you are > trying to do. > > Wouter van Ooijen > > -- ------------------------------------------- > Van Ooijen Technische Informatica: http://www.voti.nl > consultancy, development, PICmicro products > docent Hogeschool van Utrecht: http://www.voti.nl/hvu > > > --

> Thanks. Forgot to ask, will I be able to wiggle the DTR and RTS lines. > Timming is not an issue. That is definitely a less safe area than just sending and receiving data, but AFAIK yes, you can. But the timing will be affected much more than the timing of sensing/receiving data. You'd better try it before you commit a large effort to it. And YMMV depending on the brand of converter and the version of the drivers. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: http://www.voti.nl consultancy, development, PICmicro products docent Hogeschool van Utrecht: http://www.voti.nl/hvu

On Mon, 2006-01-02 at 07:26 -0800, John Pearson wrote: > Thanks. Forgot to ask, will I be able to wiggle the DTR and RTS lines. > Timming is not an issue. That's a tough one. Most will allow SOME wiggling of those lines, but some will decide what lines should be in what state, no matter what you want. Basically, if you're only using TX, RX and GND you should be fine with pretty much any USB-serial adapter. Anything more and things get iffy. TTYL ----------------------------- Herbert's PIC Stuff: http://repatch.dyndns.org:8383/pic_stuff/