Trying to initialize uart on esp32c6

Toit

#Trying to initialize uart on esp32c6

Thread channel in help

addshore 02/24/2026 03:51 PM

Running

import gpio
import uart
UART_RX_GPIO ::= 20
UART_TX_GPIO ::= 19
main:
  port := uart.Port
    --rx=gpio.Pin UART_RX_GPIO
    --tx=gpio.Pin UART_TX_GPIO
    --baud_rate=115200

Getting

Potential deadlock detected:
  Process: 2
  Program: a42ef4b4-b892-6588-9883-ce3d1e1e3b30
  BCI: 0x5c6
  Primitive: 10:1
fatal: Potential dead-lock

abort() was called at PC 0x4202f7fd on core 0
Core  0 register dump:
MEPC    : 0x40806b76  RA      : 0x4081546e  SP      : 0x40831da0  GP      : 0x40824824
TP      : 0x40831fe0  T0      : 0x37363534  T1      : 0x7271706f  T2      : 0x33323130
S0/FP   : 0x40831ddc  S1      : 0x40831ddc  A0      : 0x40831ddc  A1      : 0x40831dbe
A2      : 0x00000000  A3      : 0x40831e09  A4      : 0x00000001  A5      : 0x4082d000
A6      : 0x00000000  A7      : 0x76757473  S2      : 0x40831dc0  S3      : 0x00000001
S4      : 0x004c4b40  S5      : 0x00000005  S6      : 0x028e885f  S7      : 0x408332c0
S8      : 0x00000000  S9      : 0x00000000  S10     : 0x00000000  S11     : 0x00000000
T3      : 0x6e6d6c6b  T4      : 0x6a696867  T5      : 0x66656463  T6      : 0x62613938
MSTATUS : 0x00001881  MTVEC   : 0x40800001  MCAUSE  : 0x00000002  MTVAL   : 0x00000000
MHARTID : 0x00000000

not sure what the Primitive is, and seemignly i can only reproduce it on this hardeware setup.
Got any pointers?

addshore 02/24/2026 04:12 PM

im starting to guess its the noconsole / console esp defdault UART thing that I vaugly remember from a year ago now, and its just not a very nice error message

addshore 02/24/2026 04:25 PM

Although I just tried envelopes wiht CONFIG_ESP_CONSOLE_NONE=y etc and didnt solve it!

addshore 02/24/2026 04:48 PM

10:1 in 189 i believe is PRIMITIVE(create, 11)

floitsch 02/24/2026 05:15 PM

It's indeed 'create'. No idea how that one could block...

floitsch 02/24/2026 05:18 PM

Since you are building yourself, could you maybe add a few printfs to the function to see where it gets stuck?
https://github.com/toitlang/toit/blob/6d7fc990007289a43b49beec6871e46f73bbaee5/src/resources/uart_esp32.cc#L778

toit/src/resources/uart_esp32.cc at 6d7fc990007289a43b49beec6871e46...

Program your microcontrollers in a fast and robust high-level language. - toitlang/toit

floitsch

Since you are building yourself, could you maybe add a few printfs to the function to see where it gets stuck? https://github.com/toitlang/toit/blob/6d7fc990007289a43b49beec6871e4...

addshore 02/24/2026 05:28 PM

oh yes, im deep in these printfs now

Getting there

addshore 02/24/2026 06:36 PM

Got a patch that seems to work for me, will make a PR shortly, just walking home

addshore 02/24/2026 06:36 PM

Quite nice being able to do the full thing end to end now! Maybe I can go back and debug my i2c deadlocks

addshore 02/24/2026 07:02 PM

@floitsch

so I'm pretty sure this is what ultimately fixed my ESP32c6 https://github.com/toitlang/toit/pull/2999

esp32/uart: enable source clock before uart setup by addshore · Pu...

Add a small HAL wrapper to enable UART source clock and call it before selecting sclk/baud in uart.create. This prevents configuration against a disabled clock domain during bring-up.

addshore 02/24/2026 07:04 PM

i see conflicts with master, would be hillarious if this is already fixed in the latest release, that id idnt quite try yet, hahaha

addshore 02/24/2026 07:06 PM

Maybe I'll wait and find that out tommorrow when I have the device again and I can try v2.0.0-alpha.190 which has https://github.com/toitlang/toit/commit/6a9ee388c8c7af25554f352143a3267dfea56618

Rewrite UART (#2958) · toitlang/toit@6a9ee38

addshore 02/24/2026 07:44 PM

yup, i think you fixed the clk issue

floitsch 02/24/2026 07:45 PM

Argh. I missed that you were on 189.

addshore 02/24/2026 07:45 PM

it was a fun journey nonetheless

addshore 02/24/2026 07:45 PM

and your rewrite did fix some issues then

I expect

floitsch 02/24/2026 07:45 PM

190 has a completely rewritten uart

addshore 02/24/2026 07:46 PM

yeah, I vaugly remember it now from when you put the release notes in discord

floitsch 02/24/2026 07:46 PM

Hopefully more fixing than breaking

(edited)

addshore 02/24/2026 07:46 PM

i was already so far down the rabbit hole i didnt think about just trying to update xD(edited)

floitsch 02/24/2026 07:46 PM

floitsch 02/24/2026 07:48 PM

And well done. I had a look at fixing things with the old UART code and gave up. You actually managed to find a fix.

floitsch

And well done. I had a look at fixing things with the old UART code and gave up. You actually managed to find a fix.

addshore 02/24/2026 07:52 PM

maybe not the only one that was needed

but either way, I'll be happy to have my device UART working in the morning

addshore 02/25/2026 09:29 AM

Aaaah, @floitsch 190 is not yet in a jaguar release?

floitsch 02/25/2026 09:30 AM

No. Not yet.
190 had some big changes (like UART and esptool) and I wanted to test it a bit more before shipping it to our users with Jaguar.

addshore 02/25/2026 09:32 AM

"cleanest" way to easily use the default 190 envelope with the existing jag?

OPaddshore

"cleanest" way to easily use the default 190 envelope with the existing jag?

floitsch 02/25/2026 09:46 AM

Probably using toit-repo-path.
But I can do a 190 release soon (today?).
Especially since you have confirmed that 190 works for you.

addshore 02/25/2026 09:52 AM

Especially since you have confirmed that 190 works for you.

Still need to do that, i havnt run it just, just read the code!(edited)

addshore 02/25/2026 09:55 AM

I wonder if you might be able to look at https://github.com/toitlang/toit/pull/2998 for the same reelase?

Cant use our c3 pins without it (but again fine as I have a cyustom build for that already)

Don't restrict esp32s3 spiram pins if we don't need to by addshore ...

As far as I can tell from the data sheet, ths configuration should allow usage of these pins.

floitsch 02/25/2026 09:57 AM

That would require a new SDK release.
Note that you can use the pins with a flag. (And your PR is for s3 not c3).

addshore 02/25/2026 09:58 AM

Note that you can use the pins with a flag

ooh, that skips the check?(edited)

floitsch 02/25/2026 09:59 AM

Yes. The "restricted" can be forced

floitsch

Yes. The "restricted" can be forced

addshore 02/25/2026 12:25 PM

looks like I need / want my own envelope anyway to set the ESP with SRAM off so that I dont get warnings!

33 messages in total