Reading data from Comm

[ermingut]

I already wite code for reading and writing on comm. I have another problem. Wher I send some data to Comm my electronic ciruct returns other data (some kind of response to given command). I comunicate with 4800 bps.

Problem is this: I need to pause program while i get data from comm.

I don't know how much data will I receive (it is less than 256 bytes) and how long program must be paused.

At the moment I solved this problem with timer which trrigers every 700ms (enough time to send and recieve all data).

In my super-fast computer works fine (more or less), but when I installed program on super-slow machine (486/50) Timer execute his code every 5 seconds.

What should I do!

Ermin

[Make]

Hi Ermin!
You could try to use MSComm control. It can be used as polling or as event-driven manner. If you used it as event-driven, you'd know, for example, when output buffer is empty or when you have received data.

[ermingut]

I already use MSComm.

I yust wanna write code that will tell me that there is no "trafic" on Comm port anymore.

Because I don't know how to do that I put in timer with time set to a little more than all 256 bytes of data needs to be read from Comm (256 * 10 /4800 = 580 ms) and then I do all the stuff again (send command and read data).

Thnx!

Ermin

[Make]

I have done a couple of apps which use com port for input and output. I had similar problem: I needed to know if a whole message was received. Its length was altering, so i couldnt just check how many bytes i had received, and then determine weather the whole message was received. I solved the problem by reading all incoming data at the time it was received, and storing it into FILO(first-in-last-out) queue. After this i checked the queue for new WHOLE message(s). Checking the messages is ofcourse dependant of the protocol you use to format them.
I hope this was what you were looking for!(?)