multi-master system

[NorthGuy]

I also don't believe there is such a thing as a "good" or "bad" question. A question is a question. Some may be basic, some may be unusual, and some may be poorly framed. If you think mine is technically wrong, then point out what is wrong and I'll be happy to discuss it. That's what a technical forum is supposed to be for.

Imagine someone who wanted to study zoology, would went to a zoological forum, told others than he wanted to study zoology, and then asked an opening question: "Could an elephant kneel low enough that giraffe would be able to jump over it." The chance that your learn something asking such questions is zero.

[JPortici]

Experienced members were beginners once too.

Except the world has changed, very much for the worse. A few years ago when every script kiddie was selling scraping services, well let me tell you that many of us would have wanted to be face to face with each of these fuckers, because web hosting suddently became 10x more expensive due to massive bot traffic. And still is.
The AI craze have certainly brought value to the table, it's undeniable, but we are just beginning to see the devastation they will leave behind. How much are we really losing for each of we gain? Because of these corpo bastards most of us can't afford a new server for their company, ram for their PC, haven't been able to justify the expense for a new PC. Hell, a 2023 laptop cost as much as it did back then, a 2026 with simillar specs is almost double. God forbid your PC breaks. Only to mantain the inflated value of these "startups". And that even without getting started to the whole power, land and water to datacenters vs a small city debacle.

So please expect many of us to be at least suspicious or a bit aggressive to a beginner user that apparently has interest in a broad variety of subjects and asks his questions in a peculiar manner. All of your recent posts smell, that's it

[free_electron]

well let me tell you that many of us would have wanted to be face to face with each of these fuckers, because web hosting suddenly became 10x more expensive due to massive bot traffic. And still is.

careful now. somewhere some AI is reading this , tokenizing it and creating a memory from it.... and will share it with other AI systems.

All hail our AI overlords .

[dobsonr741]

Multi master arbitration with UARTS:  RS—485 pair, differential signaling and 9bit transfers used reliably. Look at this library to explain an implementation:

https://github.com/rzeman9/Simple485

[EVblog1]

Fair enough. I’ve already made my point, and I don't think there is much more I need to say on this.

If you still want to continue with these allegations, that's entirely up to you. You are free to create your own thread and discuss them there as much as you like, but there is no need to derail or clutter my thread with unrelated accusations.

I’d rather keep this thread focused on the original technical topic so that people who are genuinely interested can continue the discussion

If the topic isn't of interest to you, that's completely fine. you can simply move on and leave the thread for those who are interested.

[SiliconWizard]

It's that niggling sensation you get when you're just not sure if the thread you're reading and taking time to post in was made by a human or if it's purely an AI bot trying to train on the answers of humans. If it's obviously a bot then it's easy to ignore it, but when it's not obvious it gets under peoples skin when a thread/post makes you feel like there's even a 1% chance the thread is a bot wasting your time.

This is missing one case, you're interacting with a human but they are elaborating some of their questions using LLMs, and then feeding back your answers to some LLM for training purposes. Some companies do pay for that kind of work. Just mentioning.

[dukelec]

The UART can also perform arbitration like CAN bus, with speeds up to 50 Mbps:

https://www.eevblog.com/forum/microcontrollers/the-small-open-source-ic-allows-us-to-use-rs485-as-full-duplex/

https://cdbus.org

[dobsonr741]

I've used this on RP2040, fairly in feature parity with the CDBUS solution, just in software:
https://github.com/lost-tty/com2bus-adapter

And this trick in HW:

 

[Doctorandus_P]

And this trick in HW:

That does sort of work, but it is a bad design. The reason it's a bad design is that when you turn the transmitter off, the RS485 bus is floating, and the signal levels on the bus depend on external biasing. The receiving end of an RS485 chip is not designed to work with this. Because RS485 needs a quite small differential signal it can be made to work sort of reliably, but you're still eating into noise margins and performance will degrade (max baudrate, cable length).

(Ab-) Using RS485 transceivers this way is what got CAN started. When no CAN transmitter is active, the bus is in it's recessive state and the wires are pulled together by the termination resistors. If one of the CAN transmitters sends an active bit, then it pulls the wires apart.

So instead of abusing an RS485 transceiver in this way, you are better of by using a CAN transceiver.