Toit
#Serial device does not appear in Linux when connecting a board with ESP32-S2 via USB
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Jesse Sivonen 05/21/2025 11:22 AM
I cannot monitor serial messages with does appear at path
jag monitor/dev/ttyACM0jag flash
OPJesse SivonenI cannot monitor serial messages with
jag monitor
floitsch 05/21/2025 11:59 AM
I need to verify this more, but you are likely correct. The sdkconfig for the S2 does not have
Since this is an sdkconfig, it's not just something Jaguar can enable/disable, but it requires a new envelope (which contains the '.elf' file).
I have an S2 on my desk and will see if I can make the USB connection for terminal output work.
In the meantime: do you maybe have an additional esp32 or similar board lying around? The carbon S2 exposes the TX0, so if you have a board that has a USB-uart chip on it (can even be a non-esp32 chip), then you might (ab)use that board's USB-UART chip for output.
Basically, you could then just connect GND, TX0, and disable the other board (by pulling it's EN to GND).
USB CDCSince this is an sdkconfig, it's not just something Jaguar can enable/disable, but it requires a new envelope (which contains the '.elf' file).
I have an S2 on my desk and will see if I can make the USB connection for terminal output work.
In the meantime: do you maybe have an additional esp32 or similar board lying around? The carbon S2 exposes the TX0, so if you have a board that has a USB-uart chip on it (can even be a non-esp32 chip), then you might (ab)use that board's USB-UART chip for output.
Basically, you could then just connect GND, TX0, and disable the other board (by pulling it's EN to GND).
Jesse Sivonen 05/21/2025 12:14 PM
Thanks! I'll try to hijack USB-UART bridge of another board tomorrow. I don't have any other kinds of ESP32 boards except Carbon S2 currently, and I assume that they don't have the USB-UART chip, so I could try it with some older Arduino UNO or similar.(edited)
floitsch 05/21/2025 12:18 PM
That would work.
floitsch 05/21/2025 12:18 PM
I just compiled an S2 image with CDC support, but my Linux doesn't really like it:
and similar errors.
[498355.059862] cdc_acm 5-2.2:1.0: ttyACM0: USB ACM device
[498355.067022] usb 5-2.2: USB disconnect, device number 71
[498355.717746] usb 5-2.2: new full-speed USB device number 72 using xhci_hcd
[498356.302995] usb 5-2.2: device descriptor read/64, error -32
[498374.320576] usb 5-2.2: unable to read config index 0 descriptor/all
[498374.320594] usb 5-2.2: can't read configurations, error -110
[498374.408770] usb 5-2.2: new full-speed USB device number 73 using xhci_hcdand similar errors.
floitsch 05/21/2025 12:19 PM
Not completely sure, if that's my machine, the specific s2 board, or a problem with the envelope.
Jesse Sivonen 05/21/2025 12:28 PM
Hmm... So it first connects correctly (line 1), then disconnects for some reason (line 2) and tries to reconnect (line 3) but the board doesn't respond (correctly) to the "read device descriptor" request (line 4). Or something like that. I'm wondering why would it disconnect immidiately after connecting
floitsch 05/21/2025 12:30 PM
hmm. it looks like the /dev/ttyACM0 is actually appearing after some time, but I don't see it on my WiFi network.
floitsch 05/21/2025 12:30 PM
at least it appeared on my laptop. No luck yet on my desktop machine.
Jesse Sivonen 05/21/2025 12:31 PM
Have you tried some other USB port on the desktop?
floitsch 05/21/2025 12:31 PM
I just disconnected it from my hub, and trying on a different port now.
floitsch 05/21/2025 12:32 PM
I have the ttyACM0 again, but no output.
floitsch 05/21/2025 12:32 PM
Could be that it's waiting for some Jaguar message (but I don't see it appearing with
jag scanfloitsch 05/21/2025 12:34 PM
I might as well upload my envelope so you can try too.
Jesse Sivonen 05/21/2025 12:35 PM
What would happen if you typoed WiFi SSID, or password? Would it just get stuck like you have it currently?
floitsch 05/21/2025 12:36 PM
yes. but I have set my wifi credentials using
jag configJesse Sivonen 05/21/2025 12:36 PM
Right
Jesse Sivonen 05/21/2025 12:36 PM
Yea, I might have some time (maybe 20 minutes) until I have to go. So I can test it if can send the envelope
floitsch 05/21/2025 12:40 PM
on it.
floitsch 05/21/2025 12:41 PM
building
floitsch 05/21/2025 12:41 PMToit envelopes for different configurations. Contribute to toitlang/envelopes development by creating an account on GitHub.
floitsch 05/21/2025 12:41 PM
1
Once it's finished you should be able to
jag flash esp32s2-cdc1floitsch 05/21/2025 12:42 PM
assuming you have a Jaguar that wants SDK alpha-180.
floitsch 05/21/2025 12:42 PM
(run
jag versionJesse Sivonen 05/21/2025 12:43 PM1
I have it
Version: v1.51.0
SDK version: v2.0.0-alpha.180
Build date: 2025-05-10T05:48:25Z1floitsch 05/21/2025 12:43 PM
It's the latest version. so changes were pretty good 
Jesse Sivonen 05/21/2025 12:46 PM
Could this explain the disconnects?
If the application enters light sleep (including automatic light sleep) or deep sleep mode, USB CDC device will disappear from the system.
floitsch 05/21/2025 12:46 PM
Neither of those should apply for Jaguar.
floitsch 05/21/2025 12:47 PM
I recently added support for playing around with light-sleep (in the esp32 library), but you need an envelope that supports power management (and the default ones don't). It's also not something Jaguar does.
floitsch 05/21/2025 12:47 PM
And Jaguar doesn't go into deep-sleep by itself.
floitsch 05/21/2025 12:49 PM
Varinat has been built and uploaded. You should be able to use it.
floitsch 05/21/2025 12:49 PM
If it works for you, I will add it as an automatic one to our builder.
Jesse Sivonen 05/21/2025 12:53 PM
kernel: usb 1-3: new full-speed USB device number 14 using xhci_hcd
kernel: usb 1-3: device descriptor read/64, error -71
kernel: usb 1-3: device descriptor read/64, error -71
kernel: usb 1-3: new full-speed USB device number 15 using xhci_hcd
kernel: usb 1-3: device descriptor read/64, error -71
kernel: usb 1-3: device descriptor read/64, error -71
kernel: usb usb1-port3: attempt power cycle
kernel: usb 1-3: new full-speed USB device number 16 using xhci_hcd
kernel: usb 1-3: device descriptor read/8, error -71
kernel: usb 1-3: device descriptor read/8, error -71
kernel: usb 1-3: new full-speed USB device number 17 using xhci_hcd
kernel: usb 1-3: device descriptor read/8, error -71
kernel: usb 1-3: device descriptor read/8, error -71
kernel: usb usb1-port3: unable to enumerate USB deviceJesse Sivonen 05/21/2025 12:54 PM
No luck yet. But -71 is a new error?
Jesse Sivonen 05/21/2025 12:55 PM
The device can be found from the network using
jag scanfloitsch 05/21/2025 12:59 PM
I have had similar errors...
floitsch 05/21/2025 01:00 PM
The weird thing: if I just provide power (a usb cable without data), then the device seems to work and shows up on
jag scanfloitsch 05/21/2025 01:00 PM
If I connect it to my laptop, ..., then jag doesn't even seem to run.
floitsch 05/21/2025 01:00 PM
So it's likely crashing underneath (or so).
floitsch 05/21/2025 01:00 PM
Hard to tell without any debugging output.
floitsch 05/21/2025 01:04 PM1
If I find the time I might try to build an esp32s2 firmware directly from the esp-idf. Without any sdkconfig changes...
See if that works.
See if that works.
1floitsch 05/21/2025 01:58 PM
CDC works without Toit.
floitsch 05/21/2025 01:59 PM
I have furthermore changed Jaguar so that it just prints "hello" followed by a 500ms sleep. (in a loop).
This means that it doesn't even open the network (or similar).
In addition, I tried a variant where most of Toit isn't in IRAM. That didn't change anything either.
@bitphlipphar any idea of what could be causing this?
This means that it doesn't even open the network (or similar).
In addition, I tried a variant where most of Toit isn't in IRAM. That didn't change anything either.
floitsch 05/21/2025 02:03 PM
Since this only happens with the CDC I can't look at the console output to determine if the device crashes (or what the reason is), so I might need to attach a JTAG board to it. I don't think I will have the time to do that today...
floitsch 05/21/2025 06:12 PM
I managed to make the CDC work. However, the work-around is not really something we can deploy: if I delay the start of the Toit program (currently by 1s), then the device works without issues.
floitsch 05/21/2025 06:14 PM
I have asked on the esp32.com forum. Not likely we will get an answer, but just in case: https://esp32.com/viewtopic.php?p=147908
Jesse Sivonen 05/22/2025 07:23 PM
I managed to hijack Arduino UNO's USB-UART bridge chip to monitor serial log
OPJesse SivonenI managed to hijack Arduino UNO's USB-UART bridge chip to monitor serial log
floitsch 05/22/2025 08:32 PM
Nice
48 messages in total