Can chr$(0) be received using mscomm in VB? - Electronic Circuits Projects Diagrams Free

StupidDum · 23rd May 2004, 08:20 AM

In ASCII code, 0x0 represent NULL.
The VB code written by my fren could receive any other ASCII, except for chr$(0).
Could any one tell me how to do it?

Dan East · 23rd May 2004, 08:26 AM

I am not familar with BASIC (I'm program in C/C++), but ASCII 0 is used to terminate strings (when stored as null-terminated strings), and is often used as EOF (end of file) and EOT (end of transmission). If VB is interpreting ASCII 0 as any of those 3 things then it would appear not to be received.

When you receive the data, are you storing it into a string or a Byte array? You should be using the latter.

Dan East

Exo · 23rd May 2004, 08:36 AM

http://msdn.microsoft.com/library/de...ldisc_comm.asp

Exo · 23rd May 2004, 08:37 AM

http://msdn.microsoft.com/library/de...ldisc_comm.asp

StupidDum · 23rd May 2004, 01:12 PM

Quote:

Originally Posted by Exo

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/comm98/html/vbpronulldisc_comm.asp

THank a lot!!!
A few sentences solve my problem!!!!
I was thinking to re-define the communication protocol that defined by me, because the VB code written by my IT guy couldn't receive NULL

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23rd May 2004, 08:20 AM	(permalink)
StupidDum	Can chr$(0) be received using mscomm in VB? In ASCII code, 0x0 represent NULL. The VB code written by my fren could receive any other ASCII, except for chr$(0). Could any one tell me how to do it?

23rd May 2004, 08:26 AM	(permalink)
Dan East	I am not familar with BASIC (I'm program in C/C++), but ASCII 0 is used to terminate strings (when stored as null-terminated strings), and is often used as EOF (end of file) and EOT (end of transmission). If VB is interpreting ASCII 0 as any of those 3 things then it would appear not to be received. When you receive the data, are you storing it into a string or a Byte array? You should be using the latter. Dan East

23rd May 2004, 08:36 AM	(permalink)
Exo	http://msdn.microsoft.com/library/de...ldisc_comm.asp

23rd May 2004, 08:37 AM	(permalink)
Exo	http://msdn.microsoft.com/library/de...ldisc_comm.asp