1-Wire of ID of 00 00 00 00 00 00 00 00

Archiver

Hi all-
I am JUST starting to get familiar with 1-button devices, and I fairly quickly
ran into
a problem. I looked through the 1-wire posts to try and see if anyone had
similar
problems, and didn't see any. If I missed something, please accept my apologies
and
please point me to the correct posts.
Using the BS2P40 and BS2P40 demo board, I hooked up a couple of 1-buttons that

were just laying around from a previous project and tried to read their ROM data

using the 1-WIRE-ID.BSP program listed on the BS2P24 Demo Board (rev C)
instructions. I was using both a DS1990 (Not DS1990A) and two DS1994L devices.
All
three gave me the 8x00 (hex) non-signature.
I can think of a couple of potential problems, but they SEEM too lame to
cause the
non-signature signature:
(a) all three 1-button devices are about 10 years old. The signatures are
lasered into
the chip, but could the protocols have changed over the decade? (I doubt it, but

stranger things have happened ...)
(b) I used a 470k pull-up resistor, as specified in the BS2P24 demo board
instructions. Later, I noticed that the BS2P40 demo specifies a 1K pull up. I'll
of
course try it with a 1k, but within a large range of values for the 1-button,
isn't a
pull-up resistor a pull-up resistor a pull-up resistor?
(c) The code is a bit (no pun) different on the BS2P24 and BS2P40. I looked at
both
versions, and except for the fact that the 40-pin code uses AUXIO (I was using
the
main I/O pins) and the 24-pin code uses the more modern If/ElseIf/EndIF
formulation, the code looks identical.
Has anybody encountered similar problems? Does anybody have any suggestions?
Thanks for reading this far.
-Mark

Archiver

Hello,

Just a couple of months ago I was a 1-wire newbie also. The most important
skill I learned from it is how to decipher Dallas/Maxim spec sheets! [noparse]:)[/noparse]

If you are always reading zeros from your 1-wire net then that means your
voltage is not getting to the 1 logic level, check for a short!

If I recall, the simple 1-wire ID program could only work with 1 device at
a time. Try the devices 1 at a time.

I have the BS2p24 demo board Rev C. and if you are using an iButton you
just have to make sure that the jumper "iB1" is in place, it will provide
the pull up for you (4.7K). Just plug a wire from your chosen stamp pin
into the iB1 side of X2.

The size of pull-up resistor depends on the length of your wires, number of
devices, and other things. The Dallas Semiconductor spec sheets suggest
somewhere between 1K and 5K.

Chuck Chargin Jr.

At 02:01 AM 5/27/2003 +0000, you wrote:
>Hi all-
> I am JUST starting to get familiar with 1-button devices, and I fairly
> quickly ran into
>a problem. I looked through the 1-wire posts to try and see if anyone had
>similar
>problems, and didn't see any. If I missed something, please accept my
>apologies and
>please point me to the correct posts.
> Using the BS2P40 and BS2P40 demo board, I hooked up a couple of
> 1-buttons that
>were just laying around from a previous project and tried to read their
>ROM data
>using the 1-WIRE-ID.BSP program listed on the BS2P24 Demo Board (rev C)
>instructions. I was using both a DS1990 (Not DS1990A) and two DS1994L
>devices. All
>three gave me the 8x00 (hex) non-signature.
> I can think of a couple of potential problems, but they SEEM too lame
> to cause the
>non-signature signature:
>(a) all three 1-button devices are about 10 years old. The signatures are
>lasered into
>the chip, but could the protocols have changed over the decade? (I doubt
>it, but
>stranger things have happened ...)
>(b) I used a 470k pull-up resistor, as specified in the BS2P24 demo board
>instructions. Later, I noticed that the BS2P40 demo specifies a 1K pull
>up. I'll of
>course try it with a 1k, but within a large range of values for the
>1-button, isn't a
>pull-up resistor a pull-up resistor a pull-up resistor?
>(c) The code is a bit (no pun) different on the BS2P24 and BS2P40. I
>looked at both
>versions, and except for the fact that the 40-pin code uses AUXIO (I was
>using the
>main I/O pins) and the 24-pin code uses the more modern If/ElseIf/EndIF
>formulation, the code looks identical.
> Has anybody encountered similar problems? Does anybody have any
> suggestions?
>Thanks for reading this far.
>-Mark
>
>
>
>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.
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>
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Archiver

Thanks.

On Tuesday, May 27, 2003, at 01:22 AM, Chuck Chargin Jr. wrote:

> Hello,
>
> Just a couple of months ago I was a 1-wire newbie also. The most
> important
> skill I learned from it is how to decipher Dallas/Maxim spec sheets! [noparse]:)[/noparse]
>
> If you are always reading zeros from your 1-wire net then that means
> your
> voltage is not getting to the 1 logic level, check for a short!
>
> If I recall, the simple 1-wire ID program could only work with 1
> device at
> a time. Try the devices 1 at a time.
>
> I have the BS2p24 demo board Rev C. and if you are using an iButton you
> just have to make sure that the jumper "iB1" is in place, it will
> provide
> the pull up for you (4.7K). Just plug a wire from your chosen stamp
> pin
> into the iB1 side of X2.
>
> The size of pull-up resistor depends on the length of your wires,
> number of
> devices, and other things. The Dallas Semiconductor spec sheets
> suggest
> somewhere between 1K and 5K.
>
> Chuck Chargin Jr.
>
> At 02:01 AM 5/27/2003 +0000, you wrote:
>> Hi all-
>> I am JUST starting to get familiar with 1-button devices, and I
>> fairly
>> quickly ran into
>> a problem. I looked through the 1-wire posts to try and see if anyone
>> had
>> similar
>> problems, and didn't see any. If I missed something, please accept my
>> apologies and
>> please point me to the correct posts.
>> Using the BS2P40 and BS2P40 demo board, I hooked up a couple of
>> 1-buttons that
>> were just laying around from a previous project and tried to read
>> their
>> ROM data
>> using the 1-WIRE-ID.BSP program listed on the BS2P24 Demo Board (rev
>> C)
>> instructions. I was using both a DS1990 (Not DS1990A) and two DS1994L
>> devices. All
>> three gave me the 8x00 (hex) non-signature.
>> I can think of a couple of potential problems, but they SEEM too
>> lame
>> to cause the
>> non-signature signature:
>> (a) all three 1-button devices are about 10 years old. The signatures
>> are
>> lasered into
>> the chip, but could the protocols have changed over the decade? (I
>> doubt
>> it, but
>> stranger things have happened ...)
>> (b) I used a 470k pull-up resistor, as specified in the BS2P24 demo
>> board
>> instructions. Later, I noticed that the BS2P40 demo specifies a 1K
>> pull
>> up. I'll of
>> course try it with a 1k, but within a large range of values for the
>> 1-button, isn't a
>> pull-up resistor a pull-up resistor a pull-up resistor?
>> (c) The code is a bit (no pun) different on the BS2P24 and BS2P40. I
>> looked at both
>> versions, and except for the fact that the 40-pin code uses AUXIO (I
>> was
>> using the
>> main I/O pins) and the 24-pin code uses the more modern
>> If/ElseIf/EndIF
>> formulation, the code looks identical.
>> Has anybody encountered similar problems? Does anybody have any
>> suggestions?
>> Thanks for reading this far.
>> -Mark
>>
>>
>>
>> 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/
>
>
>