DIY Dallas 1 Wire Slave discussion. - Electronic Circuits Projects Diagrams Free

3v0 · 26th December 2008, 10:09 PM

For a while I have been thinking it would be interesting to write the uC code for a Dallas 1 Wire slave.

Either it is an unpopular idea, or it has been discouraged by the Maxim Dallas people. About 2 weeks ago I found a vendor document stating that they have not allocated any device addresses/types for 3rd party use. About the same time I saw what was untested BASIC code.

3v0

blueroomelectronics · 26th December 2008, 10:10 PM

There's tons of 1 wire code. Search for iButton.

3v0 · 26th December 2008, 10:14 PM

Quote:

Originally Posted by blueroomelectronics

There's tons of 1 wire code. Search for iButton.

We have all written or used code to talk to slaves. I do not see code to create a slave.

blueroomelectronics · 26th December 2008, 10:17 PM

Ahh you want to emulate an ibutton. Nope I've not seen any code for that.

3v0 · 26th December 2008, 10:23 PM

Quote:

Originally Posted by blueroomelectronics

Ahh you want to emulate an ibutton. Nope I've not seen any code for that.

Morning Bill. LOL

EDIT: I was looking for a bit of chat about the merits of creating a custom slave.

Mike, K8LH · 26th December 2008, 10:26 PM

I admit I've never thought of using the Maxim/Dallas 1-wire protocol.

I have however implemented a much higher speed Icom 1-wire (open-drain) CI-V protocol on a 12F683 based Ham radio accessory. The CI-V protocol uses standard serial data (8/1/N) at 5 volt TTL levels which necessarily limits the 1-wire bus length to relatively short distances. The packet protocol includes two header bytes ($FE, $FE), "To" and "From" address bytes, variable number of data bytes, and an $FD end-of-record byte.

Ekki DF4OR's CI-V Info' Pages

Regards, Mike

3v0 · 26th December 2008, 10:34 PM

I have been using 1 wire sensing (mostly temperature) for over two years and find them to be very durable. I have them outside, in the greenhouse and garage, and koi ponds.

In time I would like to create a monitoring, control, and security network. Speed is not important but not having to make repairs is.

There are some functions that the available 1 wire products do not address. A DIY slave based on a uC would fill the void.

Pommie · 27th December 2008, 02:19 AM

I have thought of doing this a few times. You could just make your slave look like a DS18x20 but return an invalid temperature (+127) when queried so you know it is your slave and you can then send it any custom commands you like. I thought of programming a 509 to act as a slave so I²C/SPI devices could be added to a OW bus. An obvious omission in OW devices is a humidity sensor.

<edit>Implementing the searchrom algorithm would be fun. I have managed to implement the searchrom and send RS232 on a 10f200! Fitting that into 256 words was a challenge.

</edit>

Mike.

3v0 · 27th December 2008, 02:53 AM

They have discontinued the DS2423 counter which was popular for building tip bucket type rain gauges.

I doubt one could put together a setup using parasite power but it is worth looking at. If not you will need a 3rd conductor or provide local power for the custom devices, maybe solar. Would be interesting.

Pommie · 27th December 2008, 03:42 AM

I think the parasitic power would be the easy bit. The protection diodes would conduct and so you would just need capacitors on the supply pins.

I might have a play with this in the new year.

Mike.

qratman · 28th December 2008, 02:05 PM

Here are 1-wire slave routines in asm:
Koders Code Search: 1wslave.asm - Assembler

Mike, K8LH · 28th December 2008, 02:32 PM

Thank you. That looks like a very comprehensive (and impressive) sub-system...

3v0 · 28th December 2008, 02:38 PM

I have never seen this search engine. Cool.
Now to find it in C

Quote:

Originally Posted by qratman

Here are 1-wire slave routines in asm:
Koders Code Search: 1wslave.asm - Assembler

Pommie · 28th December 2008, 03:10 PM

That is very impressive code. I'm looking forward to studying it (not now though - 1AM here).

Mike.

Mustafa · 7th January 2009, 10:15 PM

Hi,
I goggled 1wire slave and found three addresses.

First one has C code.
www.alres.pl/pub/emul_1W.zip
www.alres.pl/glowna/pomoce/emul.html
or in English Translated version

Second one, only hex code home.hetnet.nl/~thomas_7/1Wire/1-WireIOPort.html

Last one, no source code www.louisswart.co.za/1-Wire_Overview.html

Regards,
Mustafa

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26th December 2008, 10:09 PM	#1
3v0	DIY Dallas 1 Wire Slave discussion. For a while I have been thinking it would be interesting to write the uC code for a Dallas 1 Wire slave. Either it is an unpopular idea, or it has been discouraged by the Maxim Dallas people. About 2 weeks ago I found a vendor document stating that they have not allocated any device addresses/types for 3rd party use. About the same time I saw what was untested BASIC code. 3v0 __________________ Please post questions to the forums. PM's are for personal communication. BCHS/3v0's Tutorials Junebug USB PIC programmer kit., USB Bit Whacker, The 15 Minute Printed Circuit Board! (+drill time) Last edited by 3v0; 26th December 2008 at 10:12 PM.

26th December 2008, 10:10 PM	#2
blueroomelectronics	There's tons of 1 wire code. Search for iButton. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com/

26th December 2008, 10:17 PM	#4
blueroomelectronics	Ahh you want to emulate an ibutton. Nope I've not seen any code for that. __________________ Bill Smart Kits build Smart People http://www.blueroomelectronics.com/

26th December 2008, 10:26 PM	#6
Mike, K8LH	I admit I've never thought of using the Maxim/Dallas 1-wire protocol. I have however implemented a much higher speed Icom 1-wire (open-drain) CI-V protocol on a 12F683 based Ham radio accessory. The CI-V protocol uses standard serial data (8/1/N) at 5 volt TTL levels which necessarily limits the 1-wire bus length to relatively short distances. The packet protocol includes two header bytes ($FE, $FE), "To" and "From" address bytes, variable number of data bytes, and an $FD end-of-record byte. Ekki DF4OR's CI-V Info' Pages Regards, Mike Last edited by Mike, K8LH; 26th December 2008 at 10:27 PM.

26th December 2008, 10:34 PM	#7
3v0	I have been using 1 wire sensing (mostly temperature) for over two years and find them to be very durable. I have them outside, in the greenhouse and garage, and koi ponds. In time I would like to create a monitoring, control, and security network. Speed is not important but not having to make repairs is. There are some functions that the available 1 wire products do not address. A DIY slave based on a uC would fill the void. __________________ Please post questions to the forums. PM's are for personal communication. BCHS/3v0's Tutorials Junebug USB PIC programmer kit., USB Bit Whacker, The 15 Minute Printed Circuit Board! (+drill time)

27th December 2008, 02:19 AM	#8
Pommie	I have thought of doing this a few times. You could just make your slave look like a DS18x20 but return an invalid temperature (+127) when queried so you know it is your slave and you can then send it any custom commands you like. I thought of programming a 509 to act as a slave so I²C/SPI devices could be added to a OW bus. An obvious omission in OW devices is a humidity sensor. <edit>Implementing the searchrom algorithm would be fun. I have managed to implement the searchrom and send RS232 on a 10f200! Fitting that into 256 words was a challenge.</edit> Mike. Last edited by Pommie; 27th December 2008 at 02:42 AM.

27th December 2008, 02:53 AM	#9
3v0	They have discontinued the DS2423 counter which was popular for building tip bucket type rain gauges. I doubt one could put together a setup using parasite power but it is worth looking at. If not you will need a 3rd conductor or provide local power for the custom devices, maybe solar. Would be interesting. __________________ Please post questions to the forums. PM's are for personal communication. BCHS/3v0's Tutorials Junebug USB PIC programmer kit., USB Bit Whacker, The 15 Minute Printed Circuit Board! (+drill time) Last edited by 3v0; 27th December 2008 at 02:54 AM.

27th December 2008, 03:42 AM	#10
Pommie	I think the parasitic power would be the easy bit. The protection diodes would conduct and so you would just need capacitors on the supply pins. I might have a play with this in the new year. Mike.

28th December 2008, 02:05 PM	#11
qratman	Here are 1-wire slave routines in asm: Koders Code Search: 1wslave.asm - Assembler __________________ "The only thing worse than getting an error message is not getting an error message." - Allen Downey

28th December 2008, 02:32 PM	#12
Mike, K8LH	Thank you. That looks like a very comprehensive (and impressive) sub-system...

28th December 2008, 03:10 PM	#14
Pommie	That is very impressive code. I'm looking forward to studying it (not now though - 1AM here). Mike.

7th January 2009, 10:15 PM	#15
Mustafa	Hi, I goggled 1wire slave and found three addresses. First one has C code. www.alres.pl/pub/emul_1W.zip www.alres.pl/glowna/pomoce/emul.html or in English Translated version Second one, only hex code home.hetnet.nl/~thomas_7/1Wire/1-WireIOPort.html Last one, no source code www.louisswart.co.za/1-Wire_Overview.html Regards, Mustafa