UART Splitter for VESC Based ESCs

ESK8 Electronics
36

Also keen for a 1:3 :blush:

1 Like
37

Did i miss the Option to be a Beta tester? ^^

1 Like
38

Nope, not at all. I’ll put you and @StickyBlue down to be contacted when I start shipping beta kits next week :slight_smile:

1 Like
39

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 removing the pull-up) or in HW?

1 Like
40

I 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.

41

I’m I correct that this only an issue if you mix 3.3V with 5V devices? Annoying issue but a lot off track for the current concept, no?

42

This issue is actually present with an even more specific group of devices, ones that use 5v logic and have pull-up resistors attached to the UART RX pin. However, that group of devices covers most arduino based projects that communicate with the esc since the majority of arduinos have a USB to serial convert on them.

Since there are a number of arduino based projects out there that could benefit from the splitter, I dont think it’s out of scope for the project. But since the only solution I see right now is to implement an open drain output on the TX pin of each device port. A logic level shifter will have to be used until I can revise the design.

1 Like
43

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 . Please only vote once, either here or there. The name will be decided by adding up both polls.

44

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

20190716_005330_HDR

@bsancken @Wisp @Flasher @bigmisan

3 Likes
45

Would be a cool addition to have a CAN-bus <=> uart interface as well… this way you could theoretical connect unlimited devices. next step would be for makes to include a UART2CAN bridge onto theire projects :sunglasses:

1 Like
46

Yeah, I was thinking similar thing this weekend to use CAN to uart bridge as you can send same commands via CAN but I would not trust it for doing remote controls because of delays and etc…

47

yeah, I would not use it for safety related stuff (Remote) although CAN protocol is more reliable than simple UART, hence look what the world is using in cars ;-). I bridged my dual VESC 4.12 with a CAN wire as well (=remotecontrol/sync)

48

Beta testing is now underway :grin:

There are currently 6 testers with the splitter in hand. Because shipping to Europe is expensive, there are 2 more testers waiting for any other European testers to join. This would bring down shipping cost.

If anyone is interested in becoming a beta tester, please PM me.

1 Like
49

Make that 5. Mine is to arrive somewhere around the end of the week :slight_smile:

1 Like
50

The naming poll is now closed. The tally from both sites with duplicates removed is:

  • uSplit - 14
  • Splart - 9
  • Uriccosplit - 2

Thank you to all who voted :slight_smile:

2 Likes
51

Is there any update on this? :slight_smile:

1 Like
52

There are now 11 beta testers and the last beta unit is shipping out tomorrow :slight_smile:

I’ve made some improvements to the FW too:

  • Added auto rx/tx pin assignment to the ESC port (working on adding it to the device ports)
  • Added auto baud rate detection
  • Made numerous reliability improvements

I’m going to quote PCB assembly for the splitters this week. That way, once beta testing is concluded I can order a large batch of them for sale :slight_smile:

2 Likes
53

Now that all beta testing units are shipped out, I want to get an idea of how many people are interested in purchasing a uSplit once they are available.

If you would like to purchase a uSplit, please fill out this survey: https://www.surveymonkey.com/r/5MWPFC6

This will help me to know how many units to order for PCB assembly :slight_smile:

2 Likes
54

Bumping this so the survey gets more traffic.

1 Like
55

When do you think you will start selling these?

How well did it work with the firefly remote?