Ongoing development: issues and findings

[bertmelis]

I'm using this issue to track my findings and issues. If you encounter any roadblocks, feel free to add to the topic.

My setup will be a Lolin S3 mini connected to an ftdi board. This board will be connected (UART side) to another ftdi board plugged into my laptop. All boards are powered by the usb board in the laptop.

Software will be Termite (Windows) and a simple USB<>MQTT forwarder.

[bertmelis]

develop has now working code. Tested using platformio.

I'm using an ESP32-S3 and set these options

build_flags=
  ; following lines prevent the USB interface to be taken by 'Serial'
  -D ARDUINO_USB_MODE=0
  -D ARDUINO_USB_CDC_ON_BOOT=0

Depending on your hardware, you have to disable global hardwareserial objects altogether because these might interfere with the USB data lines.

[bertmelis]

When disconnecting the USB device, the ESP crashes. It's on the to do list but because I never do this, this is not my immediate priority.

[polygonfuture]

Hi @bertmelis, is there a way to connect an S3 such as an m5stack Core S3 with your library directly to a mcu such as Teensy to act as a serial monitor? Spent all day trying to get this work but realized it seems like your library only works with breakout boards that utilize FTDI etc?

I thought the S3 had capability for usb host via OTG to another usb device running in cdc mode.

My specific use would be to connect an ESP-32 S3 of the Core s3 via otg usbc adapter directly to a Teensy to read its serial output via the ESP-32 console. Aka no pc in between just direct connection tod S3 to another arduino based mcu that enables enumeration and reading of arduino mcu.

[polygonfuture]

@bertmelis Sadly this wont work as it is ESP-IDF only. It wont work when utilizing the arudino only framework which is required for the other m5stack unified firmware for the Core S3 (which includes a built in screen, camera and other peripherals)

[bertmelis]

Arduino is built on top of ESP-IDF. The m5stack runs a esp32s3? And you want to connect to the usb of the m5stack where the M5 is in CDC mode and your esp acts as host?

Do you happen to know the pod/vid? Is the m5stack software open source?

[polygonfuture]

Hey Bert, so the Core S3 is an ESP32-S3 built by m5stack. They built a board that has built in touch screen, camera, mic, lipo, charger etc. This m5stack Core S3 is the board im trying to operate as a usb host for any arduino mcu (that outputs serial messages).

My goal is to make this m5stack Core S3 (esp32-s3) into a easy plug-in serial monitor for arduino projects.

Specifically I build a lot of kinetic art works that use arduino and trying to make a very compact solution that would allow remote serial monitoring over wifi when the artwork is in an inacessible place. Specifically often hanging or out of reach from plugging a USB cable in to update firmware or bug-fix after installation.

So the goal is to have this m5stack Core S3, which has an OTG usbc port, to be able to connect an arduino to this usbc otg port, and have the ESP32 act as a usb host so it can read any serial data from the arduino.

The pid / vid would be a Teensy or other arduino based microcontroller.

I spent over a week back in June trying to get the OTG host mode working on the ESP32-S3 of the Core S3 but no library had implemented this capability easily with the arduino framework I could utilize. Tried updating existing libraries but it proved too much and a long rabbit hole that I eventually just gave up on.

m5stack has their unified device firmware which is M5Unified (here on github) but it is built upon esp-idf i believe? It mostly just unifies access to all the sensors, power management, and other periphrials and board-specific features they offer across their product line.

Im not deep enough in esp-idf to develop directly. Hence needing to develop in Arduino framework.

[bertmelis]

Look, what I can to is add a fallback scenario to the library to use CDC mode. Then you can attach any device (that runs as CDC). Absolutely no guarantees here though.

[bertmelis]

In the development branch, you can try the highly experimental (I didn't even try it myself) version with CDC fallback.

what this does:

• in your ESP32S3 USB host, you define the USBHostSerial object in the software.
• When attaching a USB device like one of the USB-to-UART dirvers, it will open a virtual com port
• If you attach a device that acts as CDC, the USBHostSerial object tries to open it to use as communication channel.
• If you plug in any other device, nothing happens.

That is at least what I hope it does. As said, highly experimental and no guarantees given whatsoever.

[noe2505]

Dude, you seriously saved me weeks or maybe months of work, i started on the same path a couple of nights ago and then i found your repo today.

Im working on connecting a Novus N1050 to an esp32-s3 board the likes of you get from aliexpress (two usb c ports on the bottom).

As of now the novus does turn on, but i only know it was detected because the esp32 crashes on disconnect (known issue, anyway when in prod there wont be physical disconnections).

Opening this msg to add my findings later and maybe get your enlightenment.

Again, thanks!

[bertmelis]

The ESP is limited in what is implemented. See here: https://components.espressif.com/components/espressif/usb_host_cdc_acm/versions/2.1.1/readme and check if your device meets the requirements.

[noe2505]

No way to check since the documentation available for the device does not go that deep in details :/ a bit at odds with this (but traveling this week so hopefully that helps clear my brain). If there's any chance you could help me debug it I can have a n1050 overnighted to you, yours to keep wether it works with esp32 or not.

[bertmelis]

No need to send a device (yet). Start by analyzing what happens when you connect it to your PC. Use https://freeusbanalyzer.com/ or something alike.

First step is to see if the device is compatible. The CDC driver is strict about what it accepts and what not (as written in the link).

[noe2505]

Back at my neck of the woods, I get the following data about the device from another tool; it looks like it's compliant for a CDC-ACM device as indicated by the link you provide:

Device Index Position: 12
Device Name: N1050

[Device Description]
Device Location ID: 0x144400
Device Set Speed: Full
Device Set Address: 0x0013
Port Information: 0x0x0018
Not Captive
External Device
Connected
Enabled

[Number Of Endpoints (includes EP0)] ✅✅
Total Endpoints for Configuration 1 (current): 4

[Device Descriptor]
Descriptor Version Number: 0x0200
Device Class: 2 (Communication)
Device Subclass: 0 ()
Device Protocol: 0 ()
Device MaxPacketSize: 8
Device MaxPacketSize: 8
Device VendorID/ProductID: 0x2044 0x1020
Device not found
Device Version Number: 0x0100
Number of Configurations: 0001
Manufacturer String (1 "Novus"):
Product String (2 N1050����):
Serial Number String (0 (none)):

[Configuration Descriptor (current config)]
Length (and contents): 67
Number of Interfaces: 2
Configuration Value: 1
Attributes: 0xC0 (self-powered)
MaxPower: 200 mA

Alternate Setting 0
Number of Endpoints 1
Interface Class: 2 - Communications-Control ✅✅
Interface Subclass: 2 - 
Interface Protocol: 1 - 

Interface #0 - @Communications-Control
Comm Class Header Functional Descriptor
Comm Class Abstract Control Management Functional Descriptor
Comm Class Union Functional Descriptor
Comm Class Call Management Functional Descriptor
Endpoint Descriptor
  Address: 0x82  (IN)
  Attributes: 0x03  (Interrupt)
  Max Packet Size: 0x0008  (8 x 1  transactions opportunities per microframe)
  Polling Interval: 2 (2 microframes (250 microsecs) )

Alternate Setting 0
Number of Endpoints 2
Interface Class: 10 - Communications-Data
Interface Subclass: 0 - Unknown Comm Class Model
Interface Protocol: 0 - 

Interface #1 - @Communications-Data/Unknown Comm Class Model
Endpoint Descriptor
  Address: 0x03  (OUT) ✅
  Attributes: 0x02  (Bulk) ✅
  Max Packet Size: 64
  Polling Interval: 0 ( Endpoint never NAKs)
Endpoint Descriptor
  Address: 0x83  (IN) ✅
  Attributes: 0x02  (Bulk) ✅
  Max Packet Size: 64
  Polling Interval: 0 ( Endpoint never NAKs)

[bertmelis]

Let's discuss this topic in #13

[polygonfuture]

@bertmelis Finally got a chance to test this on my Core S3 and a Teensy 4.1 and it works! Thank you so much Bert.

I do see the crash on unplugging but this is a great start.

I'm building a tool for the Core S3 that'll assist with debugging and uploading firmware to an Arduino connected. Once ive got it built out and working Ill share!

[bertmelis]

disconnecting is still a grey area. But very happy to hear it is working!

[andreavalle]

@bertmelis I've opened an issue due to errors I get when starting usbSerial.begin if my USB device is already connected to the ESP32-S3 OTG port. If I plug the device after starting the code, then it works nicely.

Have you seen this issue already?
How can it be avoided?

I also see the crash at disconnect, but it's not so important for me because the device is never unplugged from the host.