[[basicstamps] Bi Directional Serial Buse Problems (MORE DEAD STAMPS......)]
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Posts: 46,084
Hi all, thanks for the great replies,
The data flow is fine, until it stops.
I am using serout 9600 BPS.
Common ground, common power.
and yes, when the flow pin is damaged, it is dead for good [noparse]:([/noparse]
I will give the series resistors a go first, say 250R at the output of each
stamp. I also will tie each stamp bus line low with a 10K - any other help
is all good!!
FANX,
Dwain.
Original Message
From: "Fred Kerr (usa.net)" <fkerr@u...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, March 15, 2003 3:17 AM
Subject: Re: [noparse][[/noparse][noparse][[/noparse]basicstamps] Bi Directional Serial Buse Problems (MORE DEAD
STAMPS......)]
> I would expect that you could use some reasonable resistor values which
would
> limit current flow, etc. Also, with resistors in the circuit like that,
you
> can measure the voltage drop across them and determine the current flow.
I'm
> pretty sure that 100 ohms wouldn't cause a problem.
>
> How are they connected? I assume they have common ground. Do they have
the
> same power source? How are they routed, do the lines go near motors or
> inductive loads that might make interference with the signals? Perhaps
the
> signals should be pulled to ground with 10K-1K resistors at the sources.
> (Pull high if the signals are usually high?)
>
> You may want to consider some isolation, depending on how far the cables
are
> apart and how they are routed.
>
> Did you mean the I/O pin that you are using for flow control becomes
damaged
> on the stamp itself?
>
> Also, there may need to be a difference between signal ground and
case/chassis
> ground, to avoid ground loops.
>
> "Dwain J. Hill" <dwainsworld@e...> wrote:
> > Hi All,
> >
> >
> >
> > I have built a bi directional data bus for communication between to
stamps
> with flow control.
> >
> >
> >
> > The problem is that occasionally one of the stamps will die and refuse
to
> communicate serially any more. Nothing is shorting, each is in a nice PCB
in a
> simple circuit.
> >
> >
> >
> > It looks like it's the flow control pin that is dieing in each case.
What I
> am wondering is whether it is possible to protect each stamp pin (flow
control
> and serial data) for each stamp without effecting the data. As each stamp
is
> in a different portable box, it is necessary to protect each stamp
> individually.
> >
> >
> >
> >
> >
> > Can I do this...
> >
> >
> >
> >
|
> >
> > BS2E FLOW PIN
RESISTOR
RESISTOR
BS2E
FLOW
> PIN
> >
> >
> >
> > BS2E SD I/O DATA
RESISTOR
RESISTOR
BS2E
I/O
> DATA
> >
> >
|
> >
> > ONE BOX |
> THE OTHER BOX
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > I don't want to go for an optocoupler, unless it's absolutely necessary,
as
> I have never used one and it would require MAJOR redesign of my PCB.
Besides,
> not sure how u would make a bi-directional optocoupled bus.
> >
> >
> >
> > If the resistor method works, what values should I use?
> >
> >
> >
> > Any help appreciated,
> >
> >
> >
> > Regards,
> >
> >
> >
> > Dwain
> >
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
The data flow is fine, until it stops.
I am using serout 9600 BPS.
Common ground, common power.
and yes, when the flow pin is damaged, it is dead for good [noparse]:([/noparse]
I will give the series resistors a go first, say 250R at the output of each
stamp. I also will tie each stamp bus line low with a 10K - any other help
is all good!!
FANX,
Dwain.
Original Message
From: "Fred Kerr (usa.net)" <fkerr@u...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, March 15, 2003 3:17 AM
Subject: Re: [noparse][[/noparse][noparse][[/noparse]basicstamps] Bi Directional Serial Buse Problems (MORE DEAD
STAMPS......)]
> I would expect that you could use some reasonable resistor values which
would
> limit current flow, etc. Also, with resistors in the circuit like that,
you
> can measure the voltage drop across them and determine the current flow.
I'm
> pretty sure that 100 ohms wouldn't cause a problem.
>
> How are they connected? I assume they have common ground. Do they have
the
> same power source? How are they routed, do the lines go near motors or
> inductive loads that might make interference with the signals? Perhaps
the
> signals should be pulled to ground with 10K-1K resistors at the sources.
> (Pull high if the signals are usually high?)
>
> You may want to consider some isolation, depending on how far the cables
are
> apart and how they are routed.
>
> Did you mean the I/O pin that you are using for flow control becomes
damaged
> on the stamp itself?
>
> Also, there may need to be a difference between signal ground and
case/chassis
> ground, to avoid ground loops.
>
> "Dwain J. Hill" <dwainsworld@e...> wrote:
> > Hi All,
> >
> >
> >
> > I have built a bi directional data bus for communication between to
stamps
> with flow control.
> >
> >
> >
> > The problem is that occasionally one of the stamps will die and refuse
to
> communicate serially any more. Nothing is shorting, each is in a nice PCB
in a
> simple circuit.
> >
> >
> >
> > It looks like it's the flow control pin that is dieing in each case.
What I
> am wondering is whether it is possible to protect each stamp pin (flow
control
> and serial data) for each stamp without effecting the data. As each stamp
is
> in a different portable box, it is necessary to protect each stamp
> individually.
> >
> >
> >
> >
> >
> > Can I do this...
> >
> >
> >
> >
|
> >
> > BS2E FLOW PIN
RESISTOR
RESISTOR
BS2E
FLOW
> PIN
> >
> >
> >
> > BS2E SD I/O DATA
RESISTOR
RESISTOR
BS2E
I/O
> DATA
> >
> >
|
> >
> > ONE BOX |
> THE OTHER BOX
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > I don't want to go for an optocoupler, unless it's absolutely necessary,
as
> I have never used one and it would require MAJOR redesign of my PCB.
Besides,
> not sure how u would make a bi-directional optocoupled bus.
> >
> >
> >
> > If the resistor method works, what values should I use?
> >
> >
> >
> > Any help appreciated,
> >
> >
> >
> > Regards,
> >
> >
> >
> > Dwain
> >
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
Comments
limit current flow, etc. Also, with resistors in the circuit like that, you
can measure the voltage drop across them and determine the current flow. I'm
pretty sure that 100 ohms wouldn't cause a problem.
How are they connected? I assume they have common ground. Do they have the
same power source? How are they routed, do the lines go near motors or
inductive loads that might make interference with the signals? Perhaps the
signals should be pulled to ground with 10K-1K resistors at the sources.
(Pull high if the signals are usually high?)
You may want to consider some isolation, depending on how far the cables are
apart and how they are routed.
Did you mean the I/O pin that you are using for flow control becomes damaged
on the stamp itself?
Also, there may need to be a difference between signal ground and case/chassis
ground, to avoid ground loops.
"Dwain J. Hill" <dwainsworld@e...> wrote:
> Hi All,
>
>
>
> I have built a bi directional data bus for communication between to stamps
with flow control.
>
>
>
> The problem is that occasionally one of the stamps will die and refuse to
communicate serially any more. Nothing is shorting, each is in a nice PCB in a
simple circuit.
>
>
>
> It looks like it's the flow control pin that is dieing in each case. What I
am wondering is whether it is possible to protect each stamp pin (flow control
and serial data) for each stamp without effecting the data. As each stamp is
in a different portable box, it is necessary to protect each stamp
individually.
>
>
>
>
>
> Can I do this...
>
>
>
> |
>
> BS2E FLOW PIN
RESISTOR
RESISTOR
BS2E FLOW
PIN
>
>
>
> BS2E SD I/O DATA
RESISTOR
RESISTOR
BS2E I/O
DATA
>
> |
>
> ONE BOX |
THE OTHER BOX
>
>
>
>
>
>
>
>
>
>
>
>
>
> I don't want to go for an optocoupler, unless it's absolutely necessary, as
I have never used one and it would require MAJOR redesign of my PCB. Besides,
not sure how u would make a bi-directional optocoupled bus.
>
>
>
> If the resistor method works, what values should I use?
>
>
>
> Any help appreciated,
>
>
>
> Regards,
>
>
>
> Dwain
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
resistors of 220 ohm or more.
In addition if you are using:
SerBaud CON 84
MyData VAR BYTE
SEROUT X\Y, SerBaud, [noparse][[/noparse]MyData]
And on the other end:
SERIN X\Y, SerBaud, [noparse][[/noparse]SendData]
Then:
The 'Y' pin on SERIN will become an OUTPUT, and STAY
that way once the command ends. So, after the
SERIN, you want to say:
INPUT Y ' To turn this back to an input,
' ie high impedance, ie anybody can now 'SERIN'
' on this X\Y combo without damage.
--- In basicstamps@yahoogroups.com, "Dwain J. Hill"
<dwainsworld@e...> wrote:
> Hi all, thanks for the great replies,
>
> The data flow is fine, until it stops.
>
> I am using serout 9600 BPS.
>
> Common ground, common power.
>
> and yes, when the flow pin is damaged, it is dead for good [noparse]:([/noparse]
>
> I will give the series resistors a go first, say 250R at the output
of each
> stamp. I also will tie each stamp bus line low with a 10K - any
other help
> is all good!!
>
> FANX,
>
> Dwain.
it says the SERIN fPin stays an OUTPUT to provide
flow control to the SEROUT device -- so don't
make it an input until you're done with a
'packet'.
--- In basicstamps@yahoogroups.com, "Allan Lane" <allan.lane@h...>
wrote:
> Good, you definitely need those serial
> resistors of 220 ohm or more.
> In addition if you are using:
>
> SerBaud CON 84
> MyData VAR BYTE
>
> SEROUT X\Y, SerBaud, [noparse][[/noparse]MyData]
>
> And on the other end:
> SERIN X\Y, SerBaud, [noparse][[/noparse]SendData]
>
> Then:
> The 'Y' pin on SERIN will become an OUTPUT, and STAY
> that way once the command ends. So, after the
> SERIN, you want to say:
> INPUT Y ' To turn this back to an input,
> ' ie high impedance, ie anybody can now 'SERIN'
> ' on this X\Y combo without damage.
>
> --- In basicstamps@yahoogroups.com, "Dwain J. Hill"
> <dwainsworld@e...> wrote:
> > Hi all, thanks for the great replies,
> >
> > The data flow is fine, until it stops.
> >
> > I am using serout 9600 BPS.
> >
> > Common ground, common power.
> >
> > and yes, when the flow pin is damaged, it is dead for good [noparse]:([/noparse]
> >
> > I will give the series resistors a go first, say 250R at the
output
> of each
> > stamp. I also will tie each stamp bus line low with a 10K - any
> other help
> > is all good!!
> >
> > FANX,
> >
> > Dwain.