Re: using serial port using APIs

What baud rate are you using? How many bytes in the response?

It takes 7 ms to send a byte at 1428 baud. Usually, it takes 10 bits total
to send a byte(the byte itself+start and stop bits). So if you are sending
at 38400 Bits/Sec, that is 3840 Bytes/Sec. Each byte takes 260 us, for 7 ms,
the response can be no more than 26 bytes.

For an API approach, check newsgroups for "vb SetCommConfig"

> I would also like help on making the programme multi threaded so that the
> comm portion can be started as a separate thread so that the main
> programme
> can get on with other things while waiting for a poll.

VB6 is not multi-threaded except for ActiveX EXE's, but even that may not be
suitable(global variables are not shared between threads). I recommend that
you design your software in such away that it returns quickly from the
OnComm event. You can't show a MsgBox in OnComm event. If you have to, defer
it to a Timer.


"JamesT" <JamesT@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:A6FC7773-0B28-4302-A777-F89D7DE0E397@xxxxxxxxxxxxxxxx
>I would like to use the Windows APIs to communicate with a Device connected
> to the serial port. Can any one suggest good reading material that uses
> VB6.
> Most of what I have found gives examples in C++.
>
> The Programme is polled every 20ms by the device and the PC has to build
> the
> response ( about 7 ms) and reply very quickly. Using the MSComm control is
> too slow as the reply seems to take about 20ms to get to the device after
> the
> MSComm write command.
>
> I would also like help on making the programme multi threaded so that the
> comm portion can be started as a separate thread so that the main
> programme
> can get on with other things while waiting for a poll.
>
> Please help
>
> --
> JamesT


.

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