DS1820 on wire temp sensor using U-boot, kernel 4.14.71-ti-r80

[wal...@edenconceptsllc.com]

I am getting back in to hands-on instrumentation and controls after a long, long hiatus and struggling a bit.   I have the DS1820 one wire temperature sensor and I'm trying to understand how to get it to work with the BBB.   I'm not very experienced with Linux so I think my main struggle is with the device tree and getting all that right with U- Boot (which appears to be new.).  Most of what I can fine online refers to the deprecated method and I'd prefer not to use something that is going away for this application.  Here are some specific questions...

1. Can a device tree overly file developed for use the old way (with capemgr) be used with U-Boot?

2. If so, where do I place the compiled file so that it is loaded at boot?

3. Do I need to edit anything to make sure it gets loaded?

4. How can I be sure it loaded?

5. How do I call it in Node.js?

If I can't use the device tree overlay file developed for the old way, what do I need to do to get this going?  I'm trying to use P8_11 as the input from the sensor.

One more question - can you recommend a really good resource for learning embedded Linux for absolute beginners?   I think I need to get back to the basics and get grounded/re-grounded in this!

Thanks for helping this newbie out!

[TJF]

Hi!

When using the libpruw1 driver you won't need any device tree overlay . This driver uses libpruio for pinmuxing. Specify any (free) header pin in your source code for the W1 bus. The driver handles more than a single DS18S20 at this bus. Multiple sensors can measure simultanuosly. The driver also provides a logging feature to measure the bus state over a certain time period (for wiring tests). Examples are included in GIT repo.

Regards

[Jim F]

If you decide instead to try to get 1 W working with drivers, we failed at it on 4.14. Something changed on the way to 4.19 and we got it working there. If I had notes to share I would...if I find them.

Jim 

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[wal...@edenconceptsllc.com]

Thanks!  I'll check this out!

[wal...@edenconceptsllc.com]

Jim - I think it would be a good exercise to do it with the drivers too.  I compiled a dtbo file but I am such a novice at this.  Where do I put that file so it loads on boot?  Is there anything else I need to do to get it to load and how can I confirm that it loaded?     (

It's been two decades since I did this kind of work and a lot has changed to say the least!)  

On Tuesday, May 7, 2019 at 2:35:36 PM UTC-4, Jim F wrote:

If you decide instead to try to get 1 W working with drivers, we failed at it on 4.14. Something changed on the way to 4.19 and we got it working there. If I had notes to share I would...if I find them.

Jim 

On Tue, May 7, 2019, 10:46 AM TJF <jeli.f...@gmail.com wrote:

Hi!

When using the libpruw1 driver you won't need any device tree overlay . This driver uses libpruio for pinmuxing. Specify any (free) header pin in your source code for the W1 bus. The driver handles more than a single DS18S20 at this bus. Multiple sensors can measure simultanuosly. The driver also provides a logging feature to measure the bus state over a certain time period (for wiring tests). Examples are included in GIT repo.

Regards

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