uSplit - UART Splitter for VESC-based ESCs

Those look awesome! I’m totally gonna be using multiple of those… :laughing:

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@BillGordon Confused why this was moved into the for sale section… this is the prototyping stages still and would think @Ricco would want to create a separate for sale thread so this could stay clean for beta testers and the continued development of the 1x2 and 1x3 splitters.

Thoughts?

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Isn’t this what I2C was designed for? :woman_facepalming:

(Blaming the VESC, not you, good work on making a USB UART hub).

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This move was blessed by Ricco after a bit of back and forth. But if you feel there’s a better category fit, let him and me know. I see the thinking behind what you’re saying. Maybe an “Esk8 Prototyping” section?

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Not sure if it would make sense to have a “in beta testing”. Which would let users know they could potentially get their hands on it where as prototype would be showing off new up and coming things that aren’t available for testing yet.

I don’t know if there’s enough content to split those into 2 seperate groups though.

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Maybe an “Esk8 Dev” section?

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Ope alrighty then. I do like the Esk8 Dev idea, something similar to the Esk8 Innovation.

Stick beta and in dev threads there, then encourage new threads in for sale so that it will have up to date info on the final product at the top.


That would’ve been great if they foresaw the need for more than one or 2 accessories connected… Would love I2C based expansion…

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@BillGordon I like the new Esk8 Dev category. Splitting up the finished products and prototypes into different categories will work well.

@Gamer43, yes. I would love if the VESC platform allowed for easy addition of multiple (or any) external devices through I2C, but unfortunately thats not the path the project went down and now we have to deal with sharing one UART port with multiple add-ons :stuck_out_tongue: it is possible to use the comm port of a VESC to communicate using I2C but that requires you to make a custom app for the FW.

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Due to the recent move of this thread, can everyone who had it marked as watching or bookmarked before make sure those were retained?

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Re-bookmarked.

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sounds like maybe it’s time for a new ESC ;).

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I made some more progress today in implementing the changes needed before beta testing, but I also ran into a new issue.

When getting the Firefly remote to work, I realized that it communicates using 5v not 3.3v logic levels. The SAMD21 pins arent 5v tolerant (even though I’ve had no issue with 5v so far) but this can be solved by using series resistors on the RX pin of the external device ports.

The issue I’m having trouble figuring out is that the RX pin of the Firefly is getting pulled up to 5v internally, and when the splitter tries driving that pin low, it only pulls it down to ~2v. This isn’t always low enough for the Firefly receiver to recognize the 0 bits. Does anyone have ideas on how I can fix this in the receiver SW (possibly by disabling the pull-up) or in HW?

Would something like an external Logic Level shifter work rather than trying to implement it? Just code it to try and protect its self if it wasn’t connected correctly.

Ya, that would definitely solve the problem. I actually just figured out the cause of the issue with sending data to the Firefly reciever. The reciever is based on an arduino clone which has a USB to Serial convert IC on board. That IC pulls the RX and TX pins up to 5v with a 1k resistor no matter what pin configuration the micro is programmed with. This combined with the fact that the SAMD21 drives it’s UART TX output has the configuration below means that the RX pin of the reciever is monitoring the middle of a voltage divider and cannot be pulled lower than ~2v.

image

I would like to make the splitter as plug n’ play as possible and requiring a logic level shifter for certain devices like this defintely wouldnt fit that, but it seems thats the only option atm.

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Now that Im getting everything together for shipping beta units, its time for a poll to decided the name of the device :smiley:

  • USbR
  • Uriccosplit
  • uSplit
  • Splart

0 voters

New name suggestions are still welcome but I cant add them to the poll :confused: I can make a new poll if needed.

I posted the same poll on electric-skateboard.builders. Please only vote once, either here or there. The name will be decided by adding up both polls.

I personally prefer uSplart. :rofl:

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There are some super small package lever shifters in 8 pin package of size like sot23 just dont remember name shouldnt be too much. Or make in line shifter as you should have 3.3/5 present on cable

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Ya I plan to either use level shifter ICs or make the TX pin of each device port open drain while adding an inline resistor to the RX pin to make it 5v tolerant. I’ll weigh the pros and cons when revising the current layout.

Apparently I cant edit the poll after 5min. I’ll keep it as is. If people demand a name thats not listed, I guess I could make a new poll :stuck_out_tongue:

The first batch of beta tester units are almost ready to ship :smiley:

@bsancken @Wisp @Flasher @bigmisan

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