Depends on the platform. If you have ioctl, it's something like:
int ioctl(fd, TCSBRK, int arg);
POSIX form should have a specific function, tcsendbreak:
int tcsendbreak(fd, int arg);
You'll have to check your library to see the specifics, but the ioctl form with
and argument of 0 is usually 250-350ms.
tcsendbreak argument may be in units of 100ms, I don't recall for sure. But
that's also OS dependent. OSX ignores the value and does 400ms. Everybody does
their own thing :)
If you are working on a micro, then it's going to be different. Depends on how
serial support is implemented. You just have to drive the output low long
enough. It will be different if bit bang or UART, etc. As example, for AVR32,
Atmel has specific break generation functions in the USART library making it
pretty simple.
On Nov 29, 2011, at 8:32 PM, Roberto Spadim wrote:
yes, i´m reading it :)
only IAC BREAK is interesting, and IAC IAC (0xff character to serial), others
isn´t
but... could owserver run only with 9600 bauds? it don´t need to change baud
rate?
it only change baud rate for reset? when it need to reset?
how it send reset via serial?
put(fp,break_character); ????
or
ioctl(fp, BREAK); ???
i never sent a break via serial
2011/11/29 Ziggy <[email protected]>
Does it need to be that complex? Do you really need anything other than IAC
BREAK? I don't believe so. Only if you wish to run the DS2480 at higher than
9600 bps, which is optional. In fact, the data sheet shows that a number of
functions are not supported at higher data rates anyway.
On Nov 29, 2011, at 5:11 PM, Roberto Spadim wrote:
yeah
what i´m telling is....
udp with rfc2217
we can change baud rate via character 0xff (IAC)
and all others characters go via udp protocol :)
just change the owserver to open a udp instead of tcp
and it will never close connection, in other works, we will never know if other
side is online, like a serial line... but we can´t know if host is up or not...
(for me no problems)
2011/11/29 Ziggy <[email protected]>
After looking at this a little more closely, I don't think it will work. What I
mentioned earlier is not enough to force a 'start polarity in place of the stop
bit'. The UDP/serial converter is not going to be capable of changing it's
character format so it will still be sending 8 bit data with a valid stop bit
to the DS2480 no matter what we do. Apologies for the confusion, but I'll keep
thinking about this. It would be nice to have a streamlined UDP solution.
Ziggy
On 11/29/2011 02:27 PM, Roberto Spadim wrote:
>
> where is the rfc2217 implention in owlib?
> i want know what commands owserver send to ser2net and start the udp protocol
> in microcontroller
>
> 2011/11/29 Roberto Spadim <[email protected]>
> i will try to develop the rfc2217 in udp
> all data send via udp is sent to serial, but character 0xff allow change of
> baud rate and others thinks like rfc2217 tells
> this could work?
>
>
> 2011/11/29 Roberto Spadim <[email protected]>
> uhmmmm nice...
> well we could develop the protocol without changing baud rate?
> the reset is need for what? power up? search bus?
> could we change tcp to udp? it´s easier to implement in microcontroller
>
>
> 2011/11/29 Ziggy <[email protected]>
> You really need to read the datasheet to understand the issues. But the
> biggest issue is that of resetting the DS2480 itself, not in the 1-wire
> commands/data.
>
> You have basically two methods of resetting the chip:
> - power cycle the chip
> - reset it via software
>
> Hardware
> If the 2480 is power stealing from the serial port, you can close the
> port and reopen it, causing the control leads to toggle. This does a
> power cycle of the chip. Otherwise you need to somehow remove power from
> the chip and reapply it.
>
> Software
> The DS2480B will perform a master reset equivalent to the power-on reset
> if it detects start polarity in place of the stop bit. As described in
> the datasheet, you have a couple of methods of doing this:
>
> - send BREAK sequence
> - send character with SPACE parity
>
> A BREAK sequence is usually defined as 350ms or more of a continuous
> SPACE condition. Setting the port speed to 4800 and sending a NULL will
> cause SPACE condition for enough 9600 bps bit times that the 2480
> resets. It's sort of a simulated BREAK. This is why some 1W drivers want
> to change the port speed.
>
> With no TCP you have no telnet, and without telnet protocol you have no
> IAC BRK, which is used by terminal/port servers to generate a BREAK
> signal on the serial port. You also have no RFC2217 so no way to change
> the port speed and use the 4800 bps NULL character method. It's only the
> sending a character with SPACE parity that may work over UDP.
>
> The final thing to remember is that the DS2480B powers up in 9600 bps
> mode. So the serial port on your UDP/serial converter must be set to
> 9600 bps. This is going to limit throughput but again, without
> TCP/telnet/RFC2217 you can't change the port speed in-band via software.
>
> I guess the summary is that DS2480B on a UDP/serial converter should
> work if the DS2480B device reset is accomplished by sending the
> character with SPACE parity. Havent tried it myself though.
>
> Ziggy
>
>
> On 11/29/2011 12:13 PM, Roberto Spadim wrote:
> > hi guys, someone could explain how ds2480b works?
> > for example, what it must do with serial port (change baud rates,
> > set/read DTS RTS etc.., send / receive)
> > most important commands
> >
> > not all datasheet just some important points
> >
> > --
> > Roberto Spadim
> > Spadim Technology / SPAEmpresarial
>
> ------------------------------------------------------------------------------
> All the data continuously generated in your IT infrastructure
> contains a definitive record of customers, application performance,
> security threats, fraudulent activity, and more. Splunk takes this
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>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
>
> ------------------------------------------------------------------------------
> All the data continuously generated in your IT infrastructure
> contains a definitive record of customers, application performance,
> security threats, fraudulent activity, and more. Splunk takes this
> data and makes sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-novd2d
>
>
> _______________________________________________
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> [email protected]
> https://lists.sourceforge.net/lists/listinfo/owfs-developers
------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure
contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-novd2d
_______________________________________________
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--
Roberto Spadim
Spadim Technology / SPAEmpresarial
------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure
contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
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------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure
contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-novd2d
_______________________________________________
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--
Roberto Spadim
Spadim Technology / SPAEmpresarial
------------------------------------------------------------------------------
All the data continuously generated in your IT infrastructure
contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-novd2d_______________________________________________
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[email protected]
https://lists.sourceforge.net/lists/listinfo/owfs-developers
------------------------------------------------------------------------------
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contains a definitive record of customers, application performance,
security threats, fraudulent activity, and more. Splunk takes this
data and makes sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-novd2d
_______________________________________________
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