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'[EE]: Internet devices + java timing'
2001\10\09@124220 by D Lloyd

flavicon
face
Hi,

Problem: Internet enabling of a device purely having serial comms via the
internet.

Suppose that a simple device purely supports RS232 and has a modem so it
may be dialled up. Let's say that such a device operates quite a strict
timing regime with respect to message turnaround times and such like which
could cause some timing issues if serial comms is not handled to an
accurate timebase/timeframe.

To Internet enable this same device could, at a simplistic level, require
the following:

1. Browser running java applet which can talk to a central java application
via a socket
2. Central, muti-threaded java application servicing applet clients. This
app also perform multi-threaded serial comms to a modem....which is
attached to the RS232 device.
3. RS232 device with modem.

This is in the configuration of:
<             Internet            >                       <   Server side
Device side modem link >
Applet<----TCP/IP----->Server app<--serial-->modem<---------->modem
<---serial---->serial device

In order to contact the serial device, the applet tells the server what to
dial, then the connection is initiated via modem. The server/modem can then
hold the telephone line to the RS232 device while data is transferred
between the system end points. When the user presses the "end session"
button on the applet, the server drops the modem connection and
the.....session ends, predictably. Of course, this scenario could be
handled in CGI/Perl but let's leave it at Java for the moment.

I hear it is tricky to perform timing-sensitive serial comms in Java due to
the nature of the beast. To use another app to talk serial (i.e. one
written in C/C++) is, I imagine, a no-no for most ISPs as would be calling
C functions from Java (if that is possible).

Has anyone ever implemented such a service? If what I heard about the
timing issues is actually correct, any comments on how it is possible to
force Java to behave itself serially/interface Java to something that can
perform serial comms with an accurate timebase? Please forgive my ignorance
on the subject.

Regards,
Dan

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2001\10\09@141341 by den

picon face
To me this sounds like something for the TINI - doesn't it?

http://www.junun.org/TINI/

Sven in Sweden


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Datum: den 9 oktober 2001 18:43
Ämne: [EE]: Internet devices + java timing


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2001\10\10@024557 by D Lloyd

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face
Hi,

"For the Tini" in what respect? I was thinking of a solution without having
to deploy any TCP/IP devices at the embedded appliance end of the system;
the embedded system would preferably retain just a RS232 capability with
just a plain old modem. This means no extra hardware costs or firmware
changes, too.

To my mind, it makes far more sense to use some complicated software in a
central place (probably called through or in cooperation with a standard
web server running on a very capable platform) than increasing the hardware
end costs of the embedded systems. If the embedded devices have access to a
network (like in a factory), then that is another story.

Regards,
Dan


To: .....PICLISTKILLspamspam.....MITVMA.MIT.EDU
cc:
From: "Milton Medicinteknik KB, Vikingstad, Sweden"
<EraseMEmilton.medicinteknikspam_OUTspamTakeThisOuTTELIA.COM>
Subject: [EE]: Internet devices + java timing



To me this sounds like something for the TINI - doesn't it?

http://www.junun.org/TINI/

Sven in Sweden


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Till: @spam@PICLISTKILLspamspamMITVMA.MIT.EDU <KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU>
Datum: den 9 oktober 2001 18:43
Ämne: [EE]: Internet devices + java timing


{Quote hidden}

application
{Quote hidden}

then
>hold the telephone line to the RS232 device while data is transferred
>between the system end points. When the user presses the "end session"
>button on the applet, the server drops the modem connection and
>the.....session ends, predictably. Of course, this scenario could be
>handled in CGI/Perl but let's leave it at Java for the moment.
>
>I hear it is tricky to perform timing-sensitive serial comms in Java due
to
>the nature of the beast. To use another app to talk serial (i.e. one
>written in C/C++) is, I imagine, a no-no for most ISPs as would be calling
>C functions from Java (if that is possible).
>
>Has anyone ever implemented such a service? If what I heard about the
>timing issues is actually correct, any comments on how it is possible to
>force Java to behave itself serially/interface Java to something that can
>perform serial comms with an accurate timebase? Please forgive my
ignorance
{Quote hidden}

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2001\10\10@031629 by den

picon face
Hmmmm..

I agree with you. I am involved with a project at the moment where data is collected with PIC's, and then transferred with a TINI. My idéa was to do approximately what you suggest, but we are many involved and the concept IS TCP/IP in this case. BUT, basically, it is all - of course - very case-to-case dependant.


Sven in Sweden.

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Datum: den 10 oktober 2001 08:46
Ämne: Re: [EE]: Internet devices + java timing


{Quote hidden}

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2001\10\10@033113 by D Lloyd

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face
part 1 6764 bytes content-type:text/plain; charset=iso-8859-1 (decoded quoted-printable)



Hi,

I do agree that it is case-dependent. I have done a project recently with a
PIC talking through a hardware TCP/IP stack to a central server and the
client based approach solved many security and complexity issues.
Incidentally, do you have any idea of volume prices for Tini (say,
10k/annum?)

I have not really played around with Java IO very much so am a bit unsure
about it's timing capabilities. Speaking to one of our guys who has messed
around with the serial side of Java, he said that it wasn't easy to
guarantee timed events due to garbage collection and such like. Have you
any experience in this area?

Regards,
Dan



                                                                                        (Embedded     "Milton Medicinteknik KB, Vikingstad, Sweden"                             image moved   <RemoveMEmilton.medicinteknikTakeThisOuTspamspamTELIA.COM>TakeThisOuTspamspamMITVMA.MIT.EDU>                          to file:      10/10/2001 08:15                                                          pic04474.pcx)                                                                                                                                                                                                                                                          


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Subject:  [EE]: Internet devices + java timing

Security Level:?         Internal


Hmmmm..

I agree with you. I am involved with a project at the moment where data is
collected with PIC's, and then transferred with a TINI. My idéa was to do
approximately what you suggest, but we are many involved and the concept IS
TCP/IP in this case. BUT, basically, it is all - of course - very
case-to-case dependant.


Sven in Sweden.

-----Ursprungligt meddelande-----
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Till: KILLspamPICLISTspamBeGonespamMITVMA.MIT.EDU <EraseMEPICLISTspamEraseMEMITVMA.MIT.EDU>
Datum: den 10 oktober 2001 08:46
Ämne: Re: [EE]: Internet devices + java timing


>Hi,
>
>"For the Tini" in what respect? I was thinking of a solution without
having
>to deploy any TCP/IP devices at the embedded appliance end of the system;
>the embedded system would preferably retain just a RS232 capability with
>just a plain old modem. This means no extra hardware costs or firmware
>changes, too.
>
>To my mind, it makes far more sense to use some complicated software in a
>central place (probably called through or in cooperation with a standard
>web server running on a very capable platform) than increasing the
hardware
{Quote hidden}

which
{Quote hidden}

to
{Quote hidden}

calling
{Quote hidden}

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part 2 165 bytes content-type:application/octet-stream; (decode)

part 3 144 bytes
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2001\10\10@084903 by James Caska

picon face
Hi,

Virtual TCP-IP ;-) .. I like it. I agree that for many lower cost
applications it is overkill to have a TCP-IP capabilities "in-circuit". I
don't think many ISP's would be happy with you taking over their phone lines
though.. :-)

Another possibility is to have the java applet open a socket connection to a
TCP-IP socket server which then manages the modem, serial or other
connection however it likes. I am working on something similar called ujDX,
"Data Exchange" as part of the ujVM project.

Regards,
James Caska
.....caskaspamRemoveMEvirtualbreadboard.com
ujVM - 'The worlds smallest java virtual machine'



{Original Message removed}

2001\10\10@093519 by den

picon face
Hi,

No, I have no pricing for the TINI (other than singles). The garbage handling is done by a set of PIC's in my case. Then - over a RS232-port data is shuffeled over to a RS 232 input on a TINI - and thus to the Net. My part of it more or less ends by the interface of TINI and the application. I don't have any Java (or TINI) experience, this is handeld by others.

So - have a modem up my sleeve ;=)


Sven in Sweden

(further on this maybe you could send privately to RemoveMEmilton.medicinteknikspamspamBeGonetelia.com )





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Datum: den 10 oktober 2001 09:32
Ämne: Re: [EE]: Internet devices + java timing




Hi,

I do agree that it is case-dependent. I have done a project recently with a
PIC talking through a hardware TCP/IP stack to a central server and the
client based approach solved many security and complexity issues.
Incidentally, do you have any idea of volume prices for Tini (say,
10k/annum?)

I have not really played around with Java IO very much so am a bit unsure
about it's timing capabilities. Speaking to one of our guys who has messed
around with the serial side of Java, he said that it wasn't easy to
guarantee timed events due to garbage collection and such like. Have you
any experience in this area?

Regards,
Dan



                                                                                       (Embedded     "Milton Medicinteknik KB, Vikingstad, Sweden"                            image moved   <RemoveMEmilton.medicinteknikEraseMEspamspam_OUTTELIA.COM>EraseMEspamspam_OUTMITVMA.MIT.EDU>                         to file:      10/10/2001 08:15                                                         pic04474.pcx)                                                                                                                                                                                                                                                          


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Subject:  [EE]: Internet devices + java timing

Security Level:?         Internal


Hmmmm..

I agree with you. I am involved with a project at the moment where data is
collected with PIC's, and then transferred with a TINI. My idéa was to do
approximately what you suggest, but we are many involved and the concept IS
TCP/IP in this case. BUT, basically, it is all - of course - very
case-to-case dependant.


Sven in Sweden.

-----Ursprungligt meddelande-----
Från: D Lloyd <spamBeGonedan.lloydEraseMEspamGB.ABB.COM>
Till: PICLISTspamBeGonespamMITVMA.MIT.EDU <RemoveMEPICLIST@spam@spamspamBeGoneMITVMA.MIT.EDU>
Datum: den 10 oktober 2001 08:46
Ämne: Re: [EE]: Internet devices + java timing


>Hi,
>
>"For the Tini" in what respect? I was thinking of a solution without
having
>to deploy any TCP/IP devices at the embedded appliance end of the system;
>the embedded system would preferably retain just a RS232 capability with
>just a plain old modem. This means no extra hardware costs or firmware
>changes, too.
>
>To my mind, it makes far more sense to use some complicated software in a
>central place (probably called through or in cooperation with a standard
>web server running on a very capable platform) than increasing the
hardware
{Quote hidden}

which
{Quote hidden}

to
{Quote hidden}

calling
{Quote hidden}

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