ESP32-C2 26MHz logs don't work properly

[JurajSadel]

Log from `embassy_hello_world"

Chip type:         esp32c2 (revision v1.0)
Crystal frequency: 26MHz
Flash size:        4MB
Features:          WiFi, BLE
MAC address:       08:3a:8d:48:7d:6c
App/part. size:    89,760/4,128,768 bytes, 2.17%
[00:00:01] [========================================]      11/11      0x0
[00:00:00] [========================================]       1/1       0x8000
[00:00:02] [========================================]      22/22      0x10000
[2023-12-06T10:30:24Z INFO ] Flashing has completed!
Commands:
    CTRL+R    Reset chip
    CTRL+C    Exit

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[MabezDev]

I don't have a 26mhz board, but to be sure, you're passing the 26mhz_xtal feature too?

[JurajSadel]

Yes, I used the xtal-26mhz feature.

[bjoernQ]

I can confirm it's not working by just using the feature

However, connecting with a serialmonitor setting baud rate to 74880 ( 115200 * 26 / 40 ) gets me something

So I assume you just need to flash the right bootloader and things should be fine (since then the bootloader should set 115200 bauds correctly)

[beeb]

I have the same problem with my Sparkfun ESP32 Thing with a 26Mhz crystal. I compiled the project with the xtal-26mhz feature flag for esp32-hal (taking care to disable the default features and enable rt and vectored as well.).

I flashed with espflash -f 26mhz path/to/binary. (note that I previouly wrongly flashed a 40Mhz binary until I realized the board wasn't using 40Mhz)

Finally if I connect the monitor with espflash monitor --baud 76800 I can see the error as shown in the screenshot above:

I (28) boot: ESP-IDF v5.1-beta1-378-gea5e0ff298-dirt 2nd stage bootloader
I (28) boot: compile time Jun  7 2023 07:48:23
I (30) boot: Multicore bootloader
I (35) boot: chip revision: v1.0
I (38) boot.esp32: SPI Speed      : 40MHz
I (43) boot.esp32: SPI Mode       : DIO
I (48) boot.esp32: SPI Flash Size : 4MB
I (52) boot: Enabling RNG early entropy source...
I (58) boot: Partition Table:
I (61) boot: ## Label            Usage          Type ST Offset   Length
I (68) boot:  0 nvs              WiFi data        01 02 00009000 00006000
I (76) boot:  1 phy_init         RF data          01 01 0000f000 00001000
I (83) boot:  2 factory          factory app      00 00 00010000 003f0000
I (91) boot: End of partition table
I (95) esp_image: segment 0: paddr=00010020 vaddr=3f400020 size=041b4h ( 16820) map
I (110) esp_image: segment 1: paddr=000141dc vaddr=3ffc0000 size=00014h (    20) load
I (112) esp_image: segment 2: paddr=000141f8 vaddr=40080000 size=01b18h (  6936) load
I (123) esp_image: segment 3: paddr=00015d18 vaddr=00000000 size=0a300h ( 41728)
I (144) esp_image: segment 4: paddr=00020020 vaddr=400d0020 size=0a454h ( 42068) map
I (160) boot: Loaded app from partition at offset 0x10000
I (160) boot: Disabling RNG early entropy source...

!! A panic occured in '/home/esp/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-hal-common-0.13.1/src/rtc_cntl/rtc/esp32.rs', at line 18, column 5

PanicInfo {
    payload: Any { .. },
    message: Some(
        Did you flash the right bootloader configured for 26Mhz xtal?,
    ),
    location: Location {
        file: "/home/esp/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-hal-common-0.13.1/src/rtc_cntl/rtc/esp32.rs",
        line: 18,
        col: 5,
    },
    can_unwind: true,
    force_no_backtrace: false,
}

I have no idea how to flash a bootloader, I was under the impression that espflash would do it for me.

[SergioGasquez]

Id suggest building a bootloader in a esp-idf project and using it,see https://esp-rs.github.io/book/troubleshooting/espflash.html#rtc_clk_init-possibly-invalid-config_xtal_freq-setting.

I don't have a 26 MHz board but I can elaborate more on Monday if needed.

[beeb]

Thanks @SergioGasquez , I had not found that resource in the book.

Unfortunately, I have no esp-idf-sys-* folder in my target/xtensa-esp32-none-elf/release/build folder. Can't find any bootloader binary in fact...

I based my test on https://github.com/esp-rs/esp-template
I added a file sdkconfig.defaults to the root of the project and wrote CONFIG_XTAL_FREQ_26=y.

Using cargo espflash doesn't solve the issue for me either.

EDIT: I didn't read your post carefully. You suggest using an empty project with the https://github.com/esp-rs/esp-idf-template template to load up a bootloader, and then forget about it?

[beeb]

I'm trying to compile the project generated by esp-idf-template but it complains that ERROR: C:\tb\.embuild\espressif\espidf.constraints.v5.1.txt doesn't exist. Perhaps you've forgotten to run the install scripts. Please check the installation guide for more information.

But I don't see any install script. I used espup to install everything.

EDIT: deleting the .embuild folder and a cargo clean fixed it.

[Vollbrecht]

we are currently revisiting how the bootloader is exposed in esp-idf-sys. This is already done on gh but not released. Currently you can find the bootloader in the build artifacts of esp-idf-sys. It might look like the following inside your target dir
target/riscv32imc-<or-your-target>/debug/build/esp-idf-sys-<random-number>/out/build/bootloader

[beeb]

Cool thanks, so I am now able to build and flash my project by specifying the bootloader that was built in the idf template project. Note that if I run just cargo espflash flash --release even after a successful flash with the 26mhz bootloader, then the bootloader gets overwritten with the 40mhz one again and I have to always specify the --bootloader arg when flashing.

[SergioGasquez]

Since this issue has appeared a few times, we could try to include a 26 MHz bootloader for ESP32 and ESP32-C2 and use it if we detect a 26 MHZ freq when flashing