Basic stamp frying my serial ports -- solutions?
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I've fried 2 serial ports with my Basic Stamp. I'm using the BS2-IC.
I've connected Tx/Rx and ground to the serial connector as per
instructions in the Stamp manual. Also, I've connected DCD to +12V
(through a 2.2k resistor). I need DCD to be 1 for Linux (otherwise
Linux fails to open the serial port). The Basic Stamp is being powered
by a PC-style power supply. I feed the power supply's 12V through a
7805, then feed the 5V to the Stamp. The power supply's from an old
Compaq PC I had laying around.
Can anyone offer any advice? Has anyone else had their serial ports
fried by a Basic Stamp?
Thanks.
- Chuck Messenger
I've connected Tx/Rx and ground to the serial connector as per
instructions in the Stamp manual. Also, I've connected DCD to +12V
(through a 2.2k resistor). I need DCD to be 1 for Linux (otherwise
Linux fails to open the serial port). The Basic Stamp is being powered
by a PC-style power supply. I feed the power supply's 12V through a
7805, then feed the 5V to the Stamp. The power supply's from an old
Compaq PC I had laying around.
Can anyone offer any advice? Has anyone else had their serial ports
fried by a Basic Stamp?
Thanks.
- Chuck Messenger
Comments
connector, NOT to +12 through a resistor.
That '+12 through a resistor' thing only works
on the BS2 pins because it has VERY robust
protection diodes on it -- not true about a
'real' RS-232 driver which your PC is using.
This could be what is frying your port.
--- In basicstamps@yahoogroups.com, Chuck Messenger <chuck@c...>
wrote:
> I've fried 2 serial ports with my Basic Stamp. I'm using the BS2-
IC.
> I've connected Tx/Rx and ground to the serial connector as per
> instructions in the Stamp manual. Also, I've connected DCD to +12V
> (through a 2.2k resistor). I need DCD to be 1 for Linux (otherwise
> Linux fails to open the serial port). The Basic Stamp is being
powered
> by a PC-style power supply. I feed the power supply's 12V through
a
> 7805, then feed the 5V to the Stamp. The power supply's from an
old
> Compaq PC I had laying around.
>
> Can anyone offer any advice? Has anyone else had their serial
ports
> fried by a Basic Stamp?
>
> Thanks.
>
> - Chuck Messenger
for DCD, DTR, and DSR are connected, so when the serial port is opened by
Linux, the DTR signal goes to space (0 V and +12 V), and that drives the
DCD and DSR to space.
On my Linux computer, before I open the serial port, DTR is mark (-12 V).
When I open the serial port, DTR changes to space (+ 12 V). When the DB9
cable is connected to the NX-1000 board, the DCD and DSR pins follow the DTR
signal.
__________________
Original Message
From: "Chuck Messenger" <chuck@c...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, December 18, 2003 7:32 AM
Subject: [noparse][[/noparse]basicstamps] Basic stamp frying my serial ports -- solutions?
> I've fried 2 serial ports with my Basic Stamp. I'm using the BS2-IC.
> I've connected Tx/Rx and ground to the serial connector as per
> instructions in the Stamp manual. Also, I've connected DCD to +12V
> (through a 2.2k resistor). I need DCD to be 1 for Linux (otherwise
> Linux fails to open the serial port). The Basic Stamp is being powered
> by a PC-style power supply. I feed the power supply's 12V through a
> 7805, then feed the 5V to the Stamp. The power supply's from an old
> Compaq PC I had laying around.
>
> Can anyone offer any advice? Has anyone else had their serial ports
> fried by a Basic Stamp?
>
> Thanks.
>
> - Chuck Messenger
>
>
>
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>
>
to RESET the BS2. As such, it doesn't loop it back
at all. Now, I don't have an NX-1000 board, so I
don't know how it's wired. Plus, I'm using Windows,
so I don't know what Linux wants either.
I also believe the BOE loops RTS(7) to DSR (6),
in order to detect if the cable is connected or not.
An 'inactive' serial port should output DTR -12,
RTS -12, and TX -12. When you 'activate' the port,
DTR should go to +12, and RTS should go to +12.
--- In basicstamps@yahoogroups.com, "Steve Nelick" <s.nelick@v...>
wrote:
> I'm using Linux and a BS2. I thought that the pins on the Parallax
boards
> for DCD, DTR, and DSR are connected, so when the serial port is
opened by
> Linux, the DTR signal goes to space (0 V and +12 V), and that
drives the
> DCD and DSR to space.
>
> On my Linux computer, before I open the serial port, DTR is mark (-
12 V).
> When I open the serial port, DTR changes to space (+ 12 V). When
the DB9
> cable is connected to the NX-1000 board, the DCD and DSR pins
follow the DTR
> signal.
>
> __________________
>
>
Original Message
> From: "Chuck Messenger" <chuck@c...>
> To: <basicstamps@yahoogroups.com>
> Sent: Thursday, December 18, 2003 7:32 AM
> Subject: [noparse][[/noparse]basicstamps] Basic stamp frying my serial ports --
solutions?
>
>
> > I've fried 2 serial ports with my Basic Stamp. I'm using the BS2-
IC.
> > I've connected Tx/Rx and ground to the serial connector as per
> > instructions in the Stamp manual. Also, I've connected DCD to
+12V
> > (through a 2.2k resistor). I need DCD to be 1 for Linux
(otherwise
> > Linux fails to open the serial port). The Basic Stamp is being
powered
> > by a PC-style power supply. I feed the power supply's 12V
through a
> > 7805, then feed the 5V to the Stamp. The power supply's from an
old
> > Compaq PC I had laying around.
> >
> > Can anyone offer any advice? Has anyone else had their serial
ports
> > fried by a Basic Stamp?
> >
> > Thanks.
> >
> > - Chuck Messenger
> >
> >
> >
> > 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.
> >
> >
> > Yahoo! Groups Links
> >
> > To visit your group on the web, go to:
> > http://groups.yahoo.com/group/basicstamps/
> >
> > To unsubscribe from this group, send an email to:
> > basicstamps-unsubscribe@yahoogroups.com
> >
> > Your use of Yahoo! Groups is subject to:
> > http://docs.yahoo.com/info/terms/
> >
> >
(Board of Education). The BOE has one DB9 port for programming and
interfacing.
I've been using the Parallax NX-1000 Stamp Works Experiment Board, and the
board has two DB9 connectors. One is labeled DOWNLOAD, and the other is
labeled RS-232 INTERFACING. The one labeled DOWNLOAD, is like you said, DTR
is connected to ATN and RESET. I was using the other DB9 connector, the one
labeled RS-232 INTERFACING, and I was going by the diagram in the BASIC
STAMP MANUAL, figure 5.32 "Serial Port Diagram Showing Correct Connections
to a BASIC Stamp's I\O pin".
Getting back to Chuck's question, I guess one way to connect from Linux to
the BS2 is to not use DTR and DCD. If Chuck is using a c program, open()
has a flag , O-NDELAY, which says do not look for the DCD signal, and to
set the DTR line low, there is ioctl() and the ~TIOCM_DTR constant.
____________________
Original Message
From: "Allan Lane" <allan.lane@h...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, December 18, 2003 1:22 PM
Subject: [noparse][[/noparse]basicstamps] Re: Basic stamp frying my serial ports -- solutions?
> The BS2 'BOE' (board of education) uses DTR going high
> to RESET the BS2. As such, it doesn't loop it back
> at all. Now, I don't have an NX-1000 board, so I
> don't know how it's wired. Plus, I'm using Windows,
> so I don't know what Linux wants either.
> I also believe the BOE loops RTS(7) to DSR (6),
> in order to detect if the cable is connected or not.
>
> An 'inactive' serial port should output DTR -12,
> RTS -12, and TX -12. When you 'activate' the port,
> DTR should go to +12, and RTS should go to +12.
>
> --- In basicstamps@yahoogroups.com, "Steve Nelick" <s.nelick@v...>
> wrote:
> > I'm using Linux and a BS2. I thought that the pins on the Parallax
> boards
> > for DCD, DTR, and DSR are connected, so when the serial port is
> opened by
> > Linux, the DTR signal goes to space (0 V and +12 V), and that
> drives the
> > DCD and DSR to space.
> >
> > On my Linux computer, before I open the serial port, DTR is mark (-
> 12 V).
> > When I open the serial port, DTR changes to space (+ 12 V). When
> the DB9
> > cable is connected to the NX-1000 board, the DCD and DSR pins
> follow the DTR
> > signal.
> >
> > __________________
> >
> >
Original Message
> > From: "Chuck Messenger" <chuck@c...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Thursday, December 18, 2003 7:32 AM
> > Subject: [noparse][[/noparse]basicstamps] Basic stamp frying my serial ports --
> solutions?
> >
> >
> > > I've fried 2 serial ports with my Basic Stamp. I'm using the BS2-
> IC.
> > > I've connected Tx/Rx and ground to the serial connector as per
> > > instructions in the Stamp manual. Also, I've connected DCD to
> +12V
> > > (through a 2.2k resistor). I need DCD to be 1 for Linux
> (otherwise
> > > Linux fails to open the serial port). The Basic Stamp is being
> powered
> > > by a PC-style power supply. I feed the power supply's 12V
> through a
> > > 7805, then feed the 5V to the Stamp. The power supply's from an
> old
> > > Compaq PC I had laying around.
> > >
> > > Can anyone offer any advice? Has anyone else had their serial
> ports
> > > fried by a Basic Stamp?
> > >
> > > Thanks.
> > >
> > > - Chuck Messenger
> > >
> > >
> > >
> > > 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.
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > > To visit your group on the web, go to:
> > > http://groups.yahoo.com/group/basicstamps/
> > >
> > > To unsubscribe from this group, send an email to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > >
> > > 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.
>
>
> Yahoo! Groups Links
>
> To visit your group on the web, go to:
> http://groups.yahoo.com/group/basicstamps/
>
> To unsubscribe from this group, send an email to:
> basicstamps-unsubscribe@yahoogroups.com
>
> Your use of Yahoo! Groups is subject to:
> http://docs.yahoo.com/info/terms/
>
>
> You should probably connect DCD to DTR on the
> connector, NOT to +12 through a resistor.
>
> That '+12 through a resistor' thing only works
> on the BS2 pins because it has VERY robust
> protection diodes on it -- not true about a
> 'real' RS-232 driver which your PC is using.
> This could be what is frying your port.
>
OK, sounds promising. Thanks for the suggestion.
(and thanks to the other responders, too...)
- Chuck