serial port, RTS CTS, assembly

0
votes

i'm working on a chat using assembly, i'm using Advanced Virtual COM Port to create a COM2 and a COM3 on my pc and connect them together. I was testing a sending and a receiving program and they work fine, but only once.

By one i mean that at first, before i send the first string of chars, Advanced Virtual COM Port tells me that both COMs have this lines on: DTR, RTS, DSR, CTS and DCD. but after i send the first string and it is displayed in the receiving program, the receiving programs COM turns the RTS off and the one that sent the string turns the CTS off.

After that i can keep writing but nothing is sent or received, so, what can i do make the COMs work again? to let them know that the trasmission went right and that they can go back to their previous state, i'm using INT14h.

1
assemblyserial-portchatinterruption
You should either disable (ignore) this CTS/RTS signalling or set CTS (or is it RTS?) when you're ready to receive more data. That's it. – Alexey Frunze
CTS can not be controlled, it is an input that is normally tied to the other ends RTS than can be set. So as Alexey said, change the settings to ignore it or set RTS on both ends. – dbasnett
I'm workinng on assembly, and int14h does not allow me to do any of those things – Ricardo
never mind, I manage to set RTD by accesing the moden control register directly, thanks – Ricardo

1 Answers

0
votes

im just reposting alexey frunze comment on my question, as that was the answer but he didnt post it as one.

You should either disable (ignore) this CTS/RTS signalling or set CTS (or is it RTS?) when you're ready to receive more data. That's it