Embassy Playground 2024

Using Embassy on ESP32-C3 and C6 targets, in 2024.

Background

Based on jessebraham/esp-hal-template, but:

• supports stable in addition to nightly toolchain
• not a template repo, but a normal one

The idea is to support two kinds of targets:

• ESP32-C3-DevkitC-02 with JTAG/USB cable soldered on
• ESP32-C6-DevKitM-1 (with a dedicated JTAG/USB connector)

Requirements

Follow ESP32-Mac to set up:

• Multipass

• rust-emb VM

  Please update probe-rs to an upcoming (> 0.24.0) version. Otherwise, only works on esp32c6 chips.

   $ cargo install --git https://github.com/probe-rs/probe-rs probe-rs-tools --force
  

• USB/IP setup

• one or more of:

  • ESP32-C3-DevKitC-02 with a USB cable soldered for JTAG access

  • ESP32-C6-DevKitM-01

    This one has two USB ports (and they are USB-C :)). You can use one of them for JTAG.

Build and run (stable)

For esp32c3, use riscv32imc-unknown-none-elf and esp32c3.

$ cargo build --release --features=esp32c6 --target=riscv32imac-unknown-none-elf

$ probe-rs run --chip esp32c6 target/riscv32imac-unknown-none-elf/release/app

..with nightly (optional)

$ cargo +nightly-2024-06-01 run --features nightly,esp32c6 --release --target=riscv32imac-unknown-none-elf

Note: For the moment, one needs to have nightly < 2024-06-13 (or perhaps the patch for embassy-executor-macros). source

Running as above.

Additional

About "task arena" size

See embassy-executor > Task arena documentation.

TL;DR:

• nightly would be better. No need to provide an intended "task arena size".
• On stable, one can do that in a couple of ways (but it's presumably optional).

Troubleshooting

USB errors

If you get USB errors:

Caused by:
    0: USB Communication Error

• reset the devkit by:

  • pushing both RST and BOOT buttons
  • release the RST button
  • then release BOOT button

• reconnect the USB/IP connection:

  • RPi: usbipd bind -b 1-1.2
  • VM: usbip attach -r 192.168.1.199 -b 1-1.2

  Obviously, you'll need to use the IP and bus-id that apply to your system.

  There are ways to make a board automatically rebind on the host side; this is not covered here. Windows usbipd seems to rebind automatically.

• and try again.

Sample error case

$ make run
probe-rs run --chip esp32c6 target/riscv32imac-unknown-none-elf/release/app
      Erasing ✔ [00:00:01] [###############################################################################################################] 128.00 KiB/128.00 KiB @ 71.85 KiB/s (eta 0s )
  Programming ✔ [00:00:12] [##################################################################################################################] 26.10 KiB/26.10 KiB @ 2.12 KiB/s (eta 0s )    Finished in 15.477s
INFO  RWDT watchdog enabled!
└─ app::____embassy_main_task::{async_fn#0} @ src/bin/app.rs:47  
ERROR !! A panic occured in '/home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-hal-embassy-0.2.0/src/time_driver/mod.rs', at line 102, column 42:
└─ esp_backtrace::panic_handler @ /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-backtrace-0.13.0/src/lib.rs:29  
ERROR "panicked at /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-hal-embassy-0.2.0/src/time_driver/mod.rs:102:42:\ncalled `Option::unwrap()` on a `None` value"
└─ esp_backtrace::panic_handler @ /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-backtrace-0.13.0/src/lib.rs:29  
ERROR Backtrace:
└─ esp_backtrace::panic_handler @ /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-backtrace-0.13.0/src/lib.rs:29  
ERROR No backtrace available - make sure to force frame-pointers. (see https://crates.io/crates/esp-backtrace)
└─ esp_backtrace::panic_handler @ /home/ubuntu/.cargo/registry/src/index.crates.io-6f17d22bba15001f/esp-backtrace-0.13.0/src/lib.rs:29  
 WARN probe_rs::session: Could not clear all hardware breakpoints: An error with the usage of the probe occurred

Caused by:
    0: USB Communication Error
    1: endpoint STALL condition
thread 'main' panicked at probe-rs/src/probe/espusbjtag/protocol.rs:375:37:
range end index 77 out of range for slice of length 64
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
make: *** [Makefile:53: run] Error 101

Remote USB/IP not listed

$ usbip list -r 192.168.1.199
usbip: info: no exportable devices found on 192.168.1.199

• Reset the board as instructed above (both buttons; release RST; release BOOT).

• RPi:

   $ sudo usbip bind -b 1-1.2
  

• VM:

   $ usbip list -r 192.168.1.199
   Exportable USB devices
   ======================
    - 192.168.1.199
         1-1.2: unknown vendor : unknown product (303a:1001)
              : /sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.2
              : Miscellaneous Device / ? / Interface Association (ef/02/01)
  

That's it.