uSplit - UART Splitter for VESC-based ESCs

Movation · February 3, 2021, 5:37am

Tried to update in Win10 first in virtualbox couldnt connect. found port and drivers.
when I selected the com port is just freezed.
But it worked in native Macos

stan · June 19, 2021, 10:16am

@Ricco Hey! Long time since any update ^^.
It seems like my usplit is having some compatibility issues with newer metr.pro/davega firmware, could it be possible to have a firmware update so it could work with those devices again?
A few months ago, I had some issue with the davega, but I rolled it back to a previous compatible version, but for the metr.pro, it stopped connecting after an update in Febuary. I have recently opened my board and tested the device, the metr would work perfectly if directly connected to my ESC, but not when using the usplit. (I have the usplit on the latest 0.11 firmware.
Thanks!

Ricco · July 8, 2021, 5:03am

Sorry for taking such a long time to respond! I have been on vacation the last couple weeks and forgot to reply with everything going on.

I’ll be working on an update to the Usplit that fixes bugs seen with Metr Pro, DAVEga, and RoboGotchi over the next week.

Can you tell me what version of the Metr, DAVEga, and ESC FWs you are using right now? I know you had issues with the latest DAVEga FW before, but it sounds like this particular combination causes an issue every time you power your board. I’ll try to root out the issue in both scenarios.

stan · July 9, 2021, 8:23pm

Hello, thank you very much for your reply!
I am using the metr on version 5.36 and dual focboxes on 3.65 (vesc_tool_1.28).
My Davega died a few weeks ago and I don’t exactly remember the version it was on. My last picture of it was on version 2.0.4

ajzbern · July 13, 2021, 2:30pm

I currently have purchased the usp/it and have the focbox unity+ with flipsky vx2 pro remote and davegax coming in next week. Will these all work with the vx2 pro remote or will there be packet loss. After reading through this forum I’m not understanding. Just wondering if I should get a different remote or mod mine for ppm.

ajzbern · July 14, 2021, 9:19pm

i just got a few emails from flipsky since i have the vx2 pro remote, you can solder the ppm pin on the reciever to make the vx2 ppm, they said it should work you would just lose the screen unless u wire ppm and uart. i was trying to figure out how to use ppm since the usp/it doesnt recomment uart controllers. i have since flashed the unity BLE 115200 custom firmware to the unity with flipsky tft and vx2pro. ganna wire up the vx2 to the ble port and then usp/it the tft and get a metpro or the TTL light setup. not rly sure where this project is going lol.

ShutterShock · July 14, 2021, 9:25pm

Oh that is interesting to know

xsynatic · July 14, 2021, 10:15pm

that could be a nice workaround. Use the VX2 in PPM mode and connect the display via uSplit since it wwon’t carry important signals anymore. (i hope?)

Ricco · July 16, 2021, 4:29am

Thanks for the info. I am currently test with all the latest FWs on the Metr Pro, DAVEga, and Robogotchi. Also the FW of my ESCs is newer (not latest) than what you are running. With this setup I noticed a couple bugs that I am working to resolve.

Since our FWs are not exactly the same for all devices, your issue maybe fixed once I release a new FW version, but it also may not. If its not, then I’ll get all my FWs aligned with yours and test with an equivalent setup to sniff out the bug your encountering.

Ricco · July 16, 2021, 4:43am

This is great to know! I have wondered if this was the case since I saw the receiver has extra outputs not connected.

Ya I’m hoping this setup works. I’ll have to do some testing to see how the VX2 commands the motor over UART since I’m sure it will continue to transmit the commands. If the ESC could be configured to ignore the UART motor commands, then this would be a great work around for using the VX2 with other UART devices

Ricco · August 26, 2021, 5:35am

Sorry for the delay in getting back to you on this. I haven’t been able to put much time toward debugging lately due to work and other commitments.

I tried recreating the freezing issue you described with my setup but was not able to until I reverted to an older FW. That’s when I remembered that the older VESC FWs have an issue with UART comms freezing under heavy load. I believe that is the issue you’re experiencing. Can you try updating your ESCs to the latest FW?

moddedlife · August 26, 2021, 8:54pm

I had my davega connected to the usplit yesterday and it was working well.

I was connecting my arduino nano to the usplit. I put the 3.3v to Vin, as well as gnd tx, rx. Now no usplit lights turn on. When I try to connect to my davega again it stuck on searching for vesc. Is the usplit damaged? I tried plugging in the microusb to my PC and nothing happens.

It powers the davega on still so is it alive?

Ricco · August 27, 2021, 4:06am

Does your ESC still work properly? The Vin of the Arduino Nano is meant to be connected to 7-12v, so I am not certain what effects connecting 3v3 has, but from your description, it sounds like a high amount of current was drawn and either the ESC 3v3 burned out or the Fuse on the uSplit 3v3 pin burned out.

moddedlife · August 27, 2021, 4:40am

Yes the esc works well. I connected my davega directly and it works well. So I blew the fuse on the usplit? What can I do with it now because it doesn’t work?

Ricco · August 27, 2021, 5:09am

Ya it looks like the 3v3 fuse blew. Since it is just the fuse, you have two options:

You can remove the fuse and just bridge the two pads with solder
You can send it back to me and I’ll repair for free. You’d just have to pay shipping both ways.

moddedlife · August 27, 2021, 9:06pm

What happens if I do this? Will it risk damaging the usplit more without this fuse. All 3 of the ports don’t work. Is there 3 fuses or it’s through the esc connector then gets split into 3 after the fuse? Are there other fuses in the usplit that protect other parts? Should I look to remove more than one or you know which one it is for sure based on what I said of no ports working but power goes through (davega turns on but cant communicate with esc)

My goal is to send UART to davega and my arduino. I tried using my arduino mega and nano, and multiple different coding examples using the solid geek library. People make their own screens with arduinos to read esc data seemingly straightforwardly but I’m having so much trouble.

Do you have any suggestions for how to read UART signal through usplit with my arduino?

I wonder if the ambiguity of the tx/Rx (auto detected by usplit) is causing my arduino not to read anything? I only want to read data with the arduino so initially I tried just tx+gnd of usplit port2 going to Rx+gnd arduino. Will the usplit work like this with just two wires? Then I tried tx+Rx+gnd then 3v+gnd+tx+rx and that’s when it blew.

Anyone else have a usplit and connected with their arduino to read UART?

Here’s two examples I tried to use but didn’t work for me.

github.com

TomStanton/VESC_LCD_EBIKE/blob/master/VESC6_LCD_EBIKE.ino

/*
This code is used to gather data from a VESC6 and display on an LCD screen.
Written for Arduino Nano and LCD I2C 1602.

Original VESCUART.h code written by SolidGeek.
 */

#include <VescUart.h>
#include <SimpleKalmanFilter.h>

//Library for the Display
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16, 2); 

/** Initiate VescUart class */
VescUart UART;

int rpm;

This file has been truncated. show original

github.com

R0b0shack/VESC-UART-Arduino/blob/master/VESC_UART_Nano.ino

/*
Arduino UART communication with VESC. This software reads VESC telemetr data
and displays it on an OLED display. This code is under development for an
improved ppm remote control.

It is written by Sascha Ederer (roboshack.wordpress.com), based on the code
of jenkie (pedelecforum.de), Andreas Chaitidis (Andreas.Chaitidis@gmail.com)
and Benjamin Vedder (www.vedder.se).
Copyright (C) 2016

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

This file has been truncated. show original

Ricco · August 30, 2021, 12:47am

Bridging the pads of the fuse would make a direct connection from the ESC 3v3 to the 3v3 of the other devices connected to the uSplit. So the ESC would no longer be protected from an overcurrent event like you experienced.

There are two fuses. One on the 3v3 line and one on 5v. The fuses are on the ESC port before they get split to each of the other device ports.

For your experiments with the Arduino, I would say to try them out on the ESC directly first to rule out any uncertainty of interference by the uSplit, then add the uSplit back into the mix once it is working. Just be sure you are wiring everything up correctly since you dont want to burn up the ESC in the process.

The Arduino nano operates off 5v and since you have 5v coming from the ESC you can connect that directly to the 5v pin of the Arduino. The 3v3 pin of the Arduino doesn’t connect to anything other than the FTDI chip for USB so there is no need to connect that. The RX, TX, and GND pins you can connect accordingly.

For the UART comms. This was the library I referenced at the very beginning of the TTL project but Im guessing the SolidGeek library is just as good if not better a reference: GitHub - RollingGecko/VescUartControl: Arduino library to interface with the VESC bldc over UART.<

Ricco · October 26, 2021, 12:54am

uSplit FW v0.13 was just released. This version has the following improvements:

Fixed compatibility issues with Robogotchis configured to >2hHz refresh rate
Improved stability in setups using 2 or more ESCs and/or a BMS
Improved overall stability in the presence of heavy UART communication

The updated FW file can be found here, and instructions on updating the FW can be found here.

Dreads · October 26, 2021, 6:51pm

Thank you for continuing the update on this device.

Ricco · October 27, 2021, 5:14am

Glad you appreciate it I’ll keep fixing any bugs reported as long as I can. If I do find I cant make the time, Ill definitely give a heads up and make other arrangements like making the FW open source