Timeout in serial communication 
Author Message
 Timeout in serial communication

Hi all!
I have to get some bytes from an industrial communication device to a
PC.
So I did a search through the SWAG-archives and found some INTR $14 code

which works fine when tested in this environment (sub functions 00 to
03).
Since I don't have the industrial environment available for testing
purposes I want to
do the tests by means of two PCs. And although I use a proper cable
(switched lines
RxD and TxD and so on) [in German: "Null-Modem" ... sorry, I don't know
the English
name for it] but I get a timeout-error regardless of sending or
receiving data.
Since I kow that this works (in some environments at least), my question
is why do I get
a timeout error? Where should I look for the cause of the error?
Cabling, software,
interrupt calls?

Thanks for any help!

Greetings,
Bernd Heutling



Wed, 18 Jun 1902 08:00:00 GMT  
 Timeout in serial communication

Quote:

> Hi all!
> I have to get some bytes from an industrial communication device to a
> PC.
> So I did a search through the SWAG-archives and found some INTR $14 code

> which works fine when tested in this environment (sub functions 00 to
> 03).
> Since I don't have the industrial environment available for testing
> purposes I want to
> do the tests by means of two PCs. And although I use a proper cable
> (switched lines
> RxD and TxD and so on) [in German: "Null-Modem" ... sorry, I don't know
> the English
> name for it] but I get a timeout-error regardless of sending or
> receiving data.
> Since I kow that this works (in some environments at least), my question
> is why do I get
> a timeout error? Where should I look for the cause of the error?
> Cabling, software, interrupt calls?

Using the INT 14H under DOS will always make troubles at the Rx
side. You must do it with a hardware interrupt, that buffers the
Rxed characters in some kind of queue.

I really do not understand why the inventors of the PC found it
clever to handle the keyboard with a ROM BIOS interrupt and a
typeahead queue, but did not handle the COM ports in a similar
manner. They were obviously office type guys or even worse.
Windows at least has a proper driver for the COM ports. And
DR-Multiuser DOS has it too, for up to 64 ports on demand. It
is my preferred OS, look on my homepage for REAL/32.

http://bsn.ch/tp-links
chapter "serial" has some hints and units.
--
Franz Glaser, Glasau 3, A-4191 Vorderweissenbach Austria +43-7219-7035-0
Muehlviertler Elektronik Glaser.  Industrial control and instrumentation
http://members.eunet.at/meg-glaser/    http://members.xoom.com/f_glaser/
http://www.geocities.com/~franzglaser/            http://start.at/bedarf



Wed, 18 Jun 1902 08:00:00 GMT  
 Timeout in serial communication

"Null-Modem" is the proper name for the connection you described.



Wed, 18 Jun 1902 08:00:00 GMT  
 
 [ 3 post ] 

 Relevant Pages 

1. serial communications....

2. REQ: serial communication between 2 pc's using borland pascal for windows

3. Serial Communications interupt chaining.

4. pcl4p61.zip Personal serial communications library pascal, MarshallSoft

5. A few questions: problem with FindFirst/FindNext, serial communications and SB/SBPro access - [READ]

6. Serial communications and Parasoft MID

7. Communication on serial port

8. Help with serial communications PLEASE!

9. PLEASE HELP - need serial communication routine

10. Help me: Serial communication

11. A few questions: problem with FindFirst/FindNext, serial communications and SB/SBPro access

12. Borland Turbo 3 Serial Communication problem

 

 
Powered by phpBB® Forum Software