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]
<mailto:[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]
<mailto:[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]
<mailto:[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
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Roberto Spadim
Spadim Technology / SPAEmpresarial
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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.
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_______________________________________________
Owfs-developers mailing list
[email protected]
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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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