Serin question.
Archiver
Posts: 46,084
Hi guys,
I posted this recently but had no responses. I doubt it baffled the
brains in this groups :-) so I'm posting it again.
I hope someone can assist me interfacing a serial module to the BS2.
The specs state the unit outputs a logic high of a maximum 0.3V and a
logic low of a minimum 0.7V. There in no mention of a logic high min
(but I presume it would be close to 0V) or maximum logic low (which I
presume would be approaching 5V).
I doubt (but am not sure) the Stamp can differentiate between high
and low if they fall into this max and min range.
I can not find reference to the exact levels the stamp requires. If
it can handle these levels all well and good.
But if it can't, can anyone suggest a simple way to reliably modify
the levels to ensure a correct read. I am not very knowledgable as
far as electronics is concerned.
Thanks in advace
Col
I posted this recently but had no responses. I doubt it baffled the
brains in this groups :-) so I'm posting it again.
I hope someone can assist me interfacing a serial module to the BS2.
The specs state the unit outputs a logic high of a maximum 0.3V and a
logic low of a minimum 0.7V. There in no mention of a logic high min
(but I presume it would be close to 0V) or maximum logic low (which I
presume would be approaching 5V).
I doubt (but am not sure) the Stamp can differentiate between high
and low if they fall into this max and min range.
I can not find reference to the exact levels the stamp requires. If
it can handle these levels all well and good.
But if it can't, can anyone suggest a simple way to reliably modify
the levels to ensure a correct read. I am not very knowledgable as
far as electronics is concerned.
Thanks in advace
Col
Comments
where you can measure the levels or observe them on an oscilloscope?
What device is it? What baud rate?
The stamp switching threshold is around 1.3 volts.
If you really need to set a threshold at 0.5 volts, you can do so
with a comparator chip. Feed 0.5 volts into the (-) input, and feed
the signal into the (+) input, and viola`, the full range signal will
appear on the output. You might be able to get by with a single
transistor as the threshold detector, base to signal through a ~1kohm
resistor, emitter to common, and collector through a 10k resistor to
+5 volts. That signal is right at the transistor switching
threshold, but the workability would depend on the signal source
impedance and on the baud rate.
-- best regards
Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
>Hi guys,
>
...
>I hope someone can assist me interfacing a serial module to the BS2.
>
>The specs state the unit outputs a logic high of a maximum 0.3V and a
>logic low of a minimum 0.7V. There in no mention of a logic high min
>(but I presume it would be close to 0V) or maximum logic low (which I
>presume would be approaching 5V).
>
>I doubt (but am not sure) the Stamp can differentiate between high
>and low if they fall into this max and min range.
>
>I can not find reference to the exact levels the stamp requires. If
>it can handle these levels all well and good.
>
>But if it can't, can anyone suggest a simple way to reliably modify
>the levels to ensure a correct read. I am not very knowledgable as
>far as electronics is concerned.
>
>Thanks in advace
>
>Col
knew one of you guys could help.
I do not have the device, nor do I have an oscilloscope. I am just
going off the minimal information I was able to get off the companies
web site. They have not answered my email querie as yet.
It is a super-hetrodyne receiver working at 433.92MHz. The only info
quoted is operating voltage (5v), current, frequency, sensitivity (-
105dBm), I.F. (270KHz), Max data rate (2KHz), max signal level that
can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It is
their model RX14.)
I want to use it to send data between stamps, this module connected
via a stamp to a POS printer.
I may have to risk buying one to try it out. If the levels aren't
suitable then try your comparator solution. It's all good
experience :-)
Cheers
Col
--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> Those are very unusual levels. Do you actually have this device
> where you can measure the levels or observe them on an
oscilloscope?
> What device is it? What baud rate?
>
> The stamp switching threshold is around 1.3 volts.
>
> If you really need to set a threshold at 0.5 volts, you can do so
> with a comparator chip. Feed 0.5 volts into the (-) input, and
feed
> the signal into the (+) input, and viola`, the full range signal
will
> appear on the output. You might be able to get by with a single
> transistor as the threshold detector, base to signal through a
~1kohm
> resistor, emitter to common, and collector through a 10k resistor
to
> +5 volts. That signal is right at the transistor switching
> threshold, but the workability would depend on the signal source
> impedance and on the baud rate.
>
> -- best regards
> Tracy Allen
> electronically monitored ecosystems
> http://www.emesystems.com
> mailto:tracy@e...
>
>
> >Hi guys,
> >
> ...
>
> >I hope someone can assist me interfacing a serial module to the
BS2.
> >
> >The specs state the unit outputs a logic high of a maximum 0.3V
and a
> >logic low of a minimum 0.7V. There in no mention of a logic high
min
> >(but I presume it would be close to 0V) or maximum logic low
(which I
> >presume would be approaching 5V).
> >
> >I doubt (but am not sure) the Stamp can differentiate between high
> >and low if they fall into this max and min range.
> >
> >I can not find reference to the exact levels the stamp requires. If
> >it can handle these levels all well and good.
> >
> >But if it can't, can anyone suggest a simple way to reliably modify
> >the levels to ensure a correct read. I am not very knowledgable as
> >far as electronics is concerned.
> >
> >Thanks in advace
> >
> >Col
output of the receiver to the stamp that dropped the DC voltage
to 0
larry
Original Message
From: "aussiecol39" <aussiecol39@y...>
To: <basicstamps@yahoogroups.com>
Sent: September 12, 2002 7:53 AM
Subject: [noparse][[/noparse]basicstamps] Re: Serin question.
Thanks Tracy,
knew one of you guys could help.
I do not have the device, nor do I have an oscilloscope. I am
just
going off the minimal information I was able to get off the
companies
web site. They have not answered my email querie as yet.
It is a super-hetrodyne receiver working at 433.92MHz. The only
info
quoted is operating voltage (5v), current, frequency, sensitivity
(-
105dBm), I.F. (270KHz), Max data rate (2KHz), max signal level
that
can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It
is
their model RX14.)
I want to use it to send data between stamps, this module
connected
via a stamp to a POS printer.
I may have to risk buying one to try it out. If the levels aren't
suitable then try your comparator solution. It's all good
experience :-)
Cheers
Col
--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> Those are very unusual levels. Do you actually have this
device
> where you can measure the levels or observe them on an
oscilloscope?
> What device is it? What baud rate?
>
> The stamp switching threshold is around 1.3 volts.
>
> If you really need to set a threshold at 0.5 volts, you can do
so
> with a comparator chip. Feed 0.5 volts into the (-) input,
and
feed
> the signal into the (+) input, and viola`, the full range
signal
will
> appear on the output. You might be able to get by with a
single
> transistor as the threshold detector, base to signal through a
~1kohm
> resistor, emitter to common, and collector through a 10k
resistor
to
> +5 volts. That signal is right at the transistor switching
> threshold, but the workability would depend on the signal
source
> impedance and on the baud rate.
>
> -- best regards
> Tracy Allen
> electronically monitored ecosystems
> http://www.emesystems.com
> mailto:tracy@e...
>
>
> >Hi guys,
> >
> ...
>
> >I hope someone can assist me interfacing a serial module to
the
BS2.
> >
> >The specs state the unit outputs a logic high of a maximum
0.3V
and a
> >logic low of a minimum 0.7V. There in no mention of a logic
high
min
> >(but I presume it would be close to 0V) or maximum logic low
(which I
> >presume would be approaching 5V).
> >
> >I doubt (but am not sure) the Stamp can differentiate between
high
> >and low if they fall into this max and min range.
> >
> >I can not find reference to the exact levels the stamp
requires. If
> >it can handle these levels all well and good.
> >
> >But if it can't, can anyone suggest a simple way to reliably
modify
> >the levels to ensure a correct read. I am not very
knowledgable as
> >far as electronics is concerned.
> >
> >Thanks in advace
> >
> >Col
To UNSUBSCRIBE, just send mail to:
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output is inverted?
They are saying that a low is .7 * Vcc and a high is .3 * Vcc! So @5V
that means 0=3.5V and 1=1.5V. I suspect this is backwards. Also, usually
you'd specify your low as a MAX and your high as a MIN, so I'd be
willing to bet the MAX low is 1.5V and the MIN high is 3.5V.
Al Williams
AWC
* Easy RS-232 Prototyping
http://www.al-williams.com/awce/rs1.htm
>
Original Message
> From: aussiecol39 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=HOhumF7aIRlhbDcJmziiismps4gcz4fo0OLBcvfJRD7ULKRXgwsE5MUK0Wv2s3CV3UXfvIXE6zF8FDoBlHPe]aussiecol39@y...[/url
> Sent: Thursday, September 12, 2002 9:54 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Serin question.
>
>
> Thanks Tracy,
>
> knew one of you guys could help.
>
> I do not have the device, nor do I have an oscilloscope. I am just
> going off the minimal information I was able to get off the companies
> web site. They have not answered my email querie as yet.
>
> It is a super-hetrodyne receiver working at 433.92MHz. The only info
> quoted is operating voltage (5v), current, frequency,
> sensitivity (- 105dBm), I.F. (270KHz), Max data rate (2KHz),
> max signal level that
> can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It is
> their model RX14.)
>
> I want to use it to send data between stamps, this module connected
> via a stamp to a POS printer.
>
> I may have to risk buying one to try it out. If the levels aren't
> suitable then try your comparator solution. It's all good
> experience :-)
>
> Cheers
> Col
>
> --- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > Those are very unusual levels. Do you actually have this device
> > where you can measure the levels or observe them on an
> oscilloscope?
> > What device is it? What baud rate?
> >
> > The stamp switching threshold is around 1.3 volts.
> >
> > If you really need to set a threshold at 0.5 volts, you can do so
> > with a comparator chip. Feed 0.5 volts into the (-) input, and
> feed
> > the signal into the (+) input, and viola`, the full range signal
> will
> > appear on the output. You might be able to get by with a single
> > transistor as the threshold detector, base to signal through a
> ~1kohm
> > resistor, emitter to common, and collector through a 10k resistor
> to
> > +5 volts. That signal is right at the transistor switching
> > threshold, but the workability would depend on the signal source
> > impedance and on the baud rate.
> >
> > -- best regards
> > Tracy Allen
> > electronically monitored ecosystems
> > http://www.emesystems.com
> > mailto:tracy@e...
> >
> >
> > >Hi guys,
> > >
> > ...
> >
> > >I hope someone can assist me interfacing a serial module to the
> BS2.
> > >
> > >The specs state the unit outputs a logic high of a maximum 0.3V
> and a
> > >logic low of a minimum 0.7V. There in no mention of a logic high
> min
> > >(but I presume it would be close to 0V) or maximum logic low
> (which I
> > >presume would be approaching 5V).
> > >
> > >I doubt (but am not sure) the Stamp can differentiate between high
> > >and low if they fall into this max and min range.
> > >
> > >I can not find reference to the exact levels the stamp
> requires. If
> > >it can handle these levels all well and good.
> > >
> > >But if it can't, can anyone suggest a simple way to
> reliably modify
> > >the levels to ensure a correct read. I am not very knowledgable as
> > >far as electronics is concerned.
> > >
> > >Thanks in advace
> > >
> > >Col
>
>
> 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/
>Thanks Tracy,
>
>knew one of you guys could help.
>
>I do not have the device, nor do I have an oscilloscope. I am just
>going off the minimal information I was able to get off the companies
>web site. They have not answered my email querie as yet.
>
>It is a super-hetrodyne receiver working at 433.92MHz. The only info
>quoted is operating voltage (5v), current, frequency, sensitivity (-
>105dBm), I.F. (270KHz), Max data rate (2KHz), max signal level that
>can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It is
>their model RX14.)
>
>I want to use it to send data between stamps, this module connected
>via a stamp to a POS printer.
>
>I may have to risk buying one to try it out. If the levels aren't
>suitable then try your comparator solution. It's all good
>experience :-)
>
>Cheers
>Col
Hi Col -
You may want to check out this link where a Stamp is used with that
same receiver:
http://www.scsoftware.com.au/family/andrew/camera/remote/mk1.shtml
Please note in the list of parts the non-catalog decoder from Oatley.
Regards,
Bruce Bates
>--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > Those are very unusual levels. Do you actually have this device
> > where you can measure the levels or observe them on an
>oscilloscope?
> > What device is it? What baud rate?
> >
> > The stamp switching threshold is around 1.3 volts.
> >
> > If you really need to set a threshold at 0.5 volts, you can do so
> > with a comparator chip. Feed 0.5 volts into the (-) input, and
>feed
> > the signal into the (+) input, and viola`, the full range signal
>will
> > appear on the output. You might be able to get by with a single
> > transistor as the threshold detector, base to signal through a
>~1kohm
> > resistor, emitter to common, and collector through a 10k resistor
>to
> > +5 volts. That signal is right at the transistor switching
> > threshold, but the workability would depend on the signal source
> > impedance and on the baud rate.
> >
> > -- best regards
> > Tracy Allen
> > electronically monitored ecosystems
> > http://www.emesystems.com
> > mailto:tracy@e...
> >
> >
> > >Hi guys,
> > >
> > ...
> >
> > >I hope someone can assist me interfacing a serial module to the
>BS2.
> > >
> > >The specs state the unit outputs a logic high of a maximum 0.3V
>and a
> > >logic low of a minimum 0.7V. There in no mention of a logic high
>min
> > >(but I presume it would be close to 0V) or maximum logic low
>(which I
> > >presume would be approaching 5V).
> > >
> > >I doubt (but am not sure) the Stamp can differentiate between high
> > >and low if they fall into this max and min range.
> > >
> > >I can not find reference to the exact levels the stamp requires. If
> > >it can handle these levels all well and good.
> > >
> > >But if it can't, can anyone suggest a simple way to reliably modify
> > >the levels to ensure a correct read. I am not very knowledgable as
> > >far as electronics is concerned.
> > >
> > >Thanks in advace
> > >
> > >Col
>
>
>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/
that all makes a lot of sense. I, in my ignorance, assumed it meant a
level of .7V not that it was .7 of the 5V. I feel a lot more
confident to pursue this now :-)
Thanks again.
Cheers
Col
--- In basicstamps@y..., "Al Williams" <alw@a...> wrote:
> This is almost surely a typo in the datasheet unless it is implying
the
> output is inverted?
>
> They are saying that a low is .7 * Vcc and a high is .3 * Vcc! So
@5V
> that means 0=3.5V and 1=1.5V. I suspect this is backwards. Also,
usually
> you'd specify your low as a MAX and your high as a MIN, so I'd be
> willing to bet the MAX low is 1.5V and the MIN high is 3.5V.
>
> Al Williams
> AWC
> * Easy RS-232 Prototyping
> http://www.al-williams.com/awce/rs1.htm
>
>
>
> >
Original Message
> > From: aussiecol39 [noparse][[/noparse]mailto:aussiecol39@y...]
> > Sent: Thursday, September 12, 2002 9:54 AM
> > To: basicstamps@y...
> > Subject: [noparse][[/noparse]basicstamps] Re: Serin question.
> >
> >
> > Thanks Tracy,
> >
> > knew one of you guys could help.
> >
> > I do not have the device, nor do I have an oscilloscope. I am just
> > going off the minimal information I was able to get off the
companies
> > web site. They have not answered my email querie as yet.
> >
> > It is a super-hetrodyne receiver working at 433.92MHz. The only
info
> > quoted is operating voltage (5v), current, frequency,
> > sensitivity (- 105dBm), I.F. (270KHz), Max data rate (2KHz),
> > max signal level that
> > can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It
is
> > their model RX14.)
> >
> > I want to use it to send data between stamps, this module
connected
> > via a stamp to a POS printer.
> >
> > I may have to risk buying one to try it out. If the levels aren't
> > suitable then try your comparator solution. It's all good
> > experience :-)
> >
> > Cheers
> > Col
> >
> > --- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > > Those are very unusual levels. Do you actually have this
device
> > > where you can measure the levels or observe them on an
> > oscilloscope?
> > > What device is it? What baud rate?
> > >
> > > The stamp switching threshold is around 1.3 volts.
> > >
> > > If you really need to set a threshold at 0.5 volts, you can do
so
> > > with a comparator chip. Feed 0.5 volts into the (-) input,
and
> > feed
> > > the signal into the (+) input, and viola`, the full range signal
> > will
> > > appear on the output. You might be able to get by with a
single
> > > transistor as the threshold detector, base to signal through a
> > ~1kohm
> > > resistor, emitter to common, and collector through a 10k
resistor
> > to
> > > +5 volts. That signal is right at the transistor switching
> > > threshold, but the workability would depend on the signal
source
> > > impedance and on the baud rate.
> > >
> > > -- best regards
> > > Tracy Allen
> > > electronically monitored ecosystems
> > > http://www.emesystems.com
> > > mailto:tracy@e...
> > >
> > >
> > > >Hi guys,
> > > >
> > > ...
> > >
> > > >I hope someone can assist me interfacing a serial module to the
> > BS2.
> > > >
> > > >The specs state the unit outputs a logic high of a maximum 0.3V
> > and a
> > > >logic low of a minimum 0.7V. There in no mention of a logic
high
> > min
> > > >(but I presume it would be close to 0V) or maximum logic low
> > (which I
> > > >presume would be approaching 5V).
> > > >
> > > >I doubt (but am not sure) the Stamp can differentiate between
high
> > > >and low if they fall into this max and min range.
> > > >
> > > >I can not find reference to the exact levels the stamp
> > requires. If
> > > >it can handle these levels all well and good.
> > > >
> > > >But if it can't, can anyone suggest a simple way to
> > reliably modify
> > > >the levels to ensure a correct read. I am not very
knowledgable as
> > > >far as electronics is concerned.
> > > >
> > > >Thanks in advace
> > > >
> > > >Col
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > 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/
Thanks for that.
The link will be very useful to me not only for this project, but for
other ideas I have.
Cheers and thanks again.
Col
--- In basicstamps@y..., Bruce Bates <bvbates@u...> wrote:
> At 02:53 PM 9/12/2002 +0000, you wrote:
> >Thanks Tracy,
> >
> >knew one of you guys could help.
> >
> >I do not have the device, nor do I have an oscilloscope. I am just
> >going off the minimal information I was able to get off the
companies
> >web site. They have not answered my email querie as yet.
> >
> >It is a super-hetrodyne receiver working at 433.92MHz. The only
info
> >quoted is operating voltage (5v), current, frequency, sensitivity
(-
> >105dBm), I.F. (270KHz), Max data rate (2KHz), max signal level that
> >can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It is
> >their model RX14.)
> >
> >I want to use it to send data between stamps, this module connected
> >via a stamp to a POS printer.
> >
> >I may have to risk buying one to try it out. If the levels aren't
> >suitable then try your comparator solution. It's all good
> >experience :-)
> >
> >Cheers
> >Col
> Hi Col -
>
> You may want to check out this link where a Stamp is used with that
> same receiver:
>
http://www.scsoftware.com.au/family/andrew/camera/remote/mk1.shtml
>
> Please note in the list of parts the non-catalog decoder from
Oatley.
>
> Regards,
>
> Bruce Bates
>
>
> >--- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > > Those are very unusual levels. Do you actually have this device
> > > where you can measure the levels or observe them on an
> >oscilloscope?
> > > What device is it? What baud rate?
> > >
> > > The stamp switching threshold is around 1.3 volts.
> > >
> > > If you really need to set a threshold at 0.5 volts, you can do
so
> > > with a comparator chip. Feed 0.5 volts into the (-) input, and
> >feed
> > > the signal into the (+) input, and viola`, the full range signal
> >will
> > > appear on the output. You might be able to get by with a single
> > > transistor as the threshold detector, base to signal through a
> >~1kohm
> > > resistor, emitter to common, and collector through a 10k
resistor
> >to
> > > +5 volts. That signal is right at the transistor switching
> > > threshold, but the workability would depend on the signal source
> > > impedance and on the baud rate.
> > >
> > > -- best regards
> > > Tracy Allen
> > > electronically monitored ecosystems
> > > http://www.emesystems.com
> > > mailto:tracy@e...
> > >
> > >
> > > >Hi guys,
> > > >
> > > ...
> > >
> > > >I hope someone can assist me interfacing a serial module to the
> >BS2.
> > > >
> > > >The specs state the unit outputs a logic high of a maximum 0.3V
> >and a
> > > >logic low of a minimum 0.7V. There in no mention of a logic
high
> >min
> > > >(but I presume it would be close to 0V) or maximum logic low
> >(which I
> > > >presume would be approaching 5V).
> > > >
> > > >I doubt (but am not sure) the Stamp can differentiate between
high
> > > >and low if they fall into this max and min range.
> > > >
> > > >I can not find reference to the exact levels the stamp
requires. If
> > > >it can handle these levels all well and good.
> > > >
> > > >But if it can't, can anyone suggest a simple way to reliably
modify
> > > >the levels to ensure a correct read. I am not very
knowledgable as
> > > >far as electronics is concerned.
> > > >
> > > >Thanks in advace
> > > >
> > > >Col
> >
> >
> >To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> >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/
could be an option. Still, I think I need an oscilloscope to sus out
exactly what the outputs are :-)
Cheers
Col
--- In basicstamps@y..., "Larry Gaminde" <lgaminde@t...> wrote:
> What I did on my rf receiver is use a .01 or .1 cap from the
> output of the receiver to the stamp that dropped the DC voltage
> to 0
>
> larry
>
>
Original Message
> From: "aussiecol39" <aussiecol39@y...>
> To: <basicstamps@y...>
> Sent: September 12, 2002 7:53 AM
> Subject: [noparse][[/noparse]basicstamps] Re: Serin question.
>
>
> Thanks Tracy,
>
> knew one of you guys could help.
>
> I do not have the device, nor do I have an oscilloscope. I am
> just
> going off the minimal information I was able to get off the
> companies
> web site. They have not answered my email querie as yet.
>
> It is a super-hetrodyne receiver working at 433.92MHz. The only
> info
> quoted is operating voltage (5v), current, frequency, sensitivity
> (-
> 105dBm), I.F. (270KHz), Max data rate (2KHz), max signal level
> that
> can be decoded (-23.5dBm). (http://www.oatleyelectronics.com It
> is
> their model RX14.)
>
> I want to use it to send data between stamps, this module
> connected
> via a stamp to a POS printer.
>
> I may have to risk buying one to try it out. If the levels aren't
> suitable then try your comparator solution. It's all good
> experience :-)
>
> Cheers
> Col
>
> --- In basicstamps@y..., Tracy Allen <tracy@e...> wrote:
> > Those are very unusual levels. Do you actually have this
> device
> > where you can measure the levels or observe them on an
> oscilloscope?
> > What device is it? What baud rate?
> >
> > The stamp switching threshold is around 1.3 volts.
> >
> > If you really need to set a threshold at 0.5 volts, you can do
> so
> > with a comparator chip. Feed 0.5 volts into the (-) input,
> and
> feed
> > the signal into the (+) input, and viola`, the full range
> signal
> will
> > appear on the output. You might be able to get by with a
> single
> > transistor as the threshold detector, base to signal through a
> ~1kohm
> > resistor, emitter to common, and collector through a 10k
> resistor
> to
> > +5 volts. That signal is right at the transistor switching
> > threshold, but the workability would depend on the signal
> source
> > impedance and on the baud rate.
> >
> > -- best regards
> > Tracy Allen
> > electronically monitored ecosystems
> > http://www.emesystems.com
> > mailto:tracy@e...
> >
> >
> > >Hi guys,
> > >
> > ...
> >
> > >I hope someone can assist me interfacing a serial module to
> the
> BS2.
> > >
> > >The specs state the unit outputs a logic high of a maximum
> 0.3V
> and a
> > >logic low of a minimum 0.7V. There in no mention of a logic
> high
> min
> > >(but I presume it would be close to 0V) or maximum logic low
> (which I
> > >presume would be approaching 5V).
> > >
> > >I doubt (but am not sure) the Stamp can differentiate between
> high
> > >and low if they fall into this max and min range.
> > >
> > >I can not find reference to the exact levels the stamp
> requires. If
> > >it can handle these levels all well and good.
> > >
> > >But if it can't, can anyone suggest a simple way to reliably
> modify
> > >the levels to ensure a correct read. I am not very
> knowledgable as
> > >far as electronics is concerned.
> > >
> > >Thanks in advace
> > >
> > >Col
>
>
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