Some help about COM PORT

[TronicBrain]

Hi every one

I have started my first project about Serial communication between my 16F877 and my PC using MAX232
Every thing is ready and waiting for powering on.

But there is one thing that stops me
I got the information from mikroelektronika web site
As they say that I have to connected the com port as following
DTR & DSR & CD as one point
RTS & CTS as on point

Is it possible to let these five pines free?
Will not that cause damage to my com port?

Any one have some experience about that?

 

[Nigel Goodwin]

They are handshake lines, as long as you have handshaking turned OFF then you can just ignore them.

 

[Electrix]

They are handshake lines, as long as you have handshaking turned OFF then you can just ignore them.

Isn't that called a NULL Modem Connection ..sort of a loop back connection..to enable the PC to generate its own readiness and receive its acknowledgement too..

 

[Jay.slovak]

They are handshake lines, as long as you have handshaking turned OFF then you can just ignore them.

Isn't that called a NULL Modem Connection ..sort of a loop back connection..to enable the PC to generate its own readiness and receive its acknowledgement too..

It is, but you only need it when you want to disable "HW Handshaking", if you don't use it, those pins are NC.

 

[destinywaste]

It is hundres percent OK. DTR/DSR/CD, RTS/CTS lines are used for handshake. If you not interested you can disconnect them. But if the program is using handshaking, then it asserts DTR wait for DSR or asserts RTS and waits for CTS. To overcome this the technik of coonecting them together is a standard mechanism. It wont cause ant damage to the port.

 

[panic mode]

you can gain some experience if you connect this cable to two com ports of your pc and open each in hyperterminal (or any other terminal of your choice). try different settings and see what happens. it doesn't have to be same computer (really try it out). you can remove the jumpers and leave only three wires and you will see for yourself what the other posts suggest - it will work as long no handshaking is used.

 

[TronicBrain]

Thank you very much guys

every thing is working well now

I wrote my own program which can communicate via comport using Delphi

It's really interesting to make your own project which connected to pc

now I'm getting more familiar with it

Thanks again

 

[destinywaste]

Thank you very much guys

every thing is working well now

I wrote my own program which can communicate via comport using Delphi

It's really interesting to make your own project which connected to pc

now I'm getting more familiar with it

Thanks again

have fun :lol: :lol: :lol: