Rust ESP32 Community Meeting 2022-03-29

[georgik]

Please add topics and links to this discussion.

The meeting is scheduled 29st March 2022 - 5pm CEST/GMT+2 via Google Meet. The meeting invite is automatically sent to attendees of previous meetings. If you'd like to join, please notify us at https://matrix.to/#/#esp-rs-community-meetins:matrix.org

You can find information from previous meeting at https://github.com/esp-rs/rust/discussions

[ivmarkov]

esp-idf-*

• New releases with native build by default (pending updates to esp-idf-template and rust-esp32-std-demo)

embedded-svc / esp-idf-svc

• Working ESP-IDF HTTPD WebSocket wrappers (including async support)

edge-frame (Minimal Web Frontend for IOT devices)

• Re-built from the ground-up with Rust Yew functional components and Bulma
• Current size: ~ 200K compressed (all web app assets)
• Published at crates.io
• Besides web components, also features for easy building & bundling of web assets (the web app) as part of the firmware
• Needs (simple) documentation

RUWM

• Has a minimal Web Frontend now (^^^) and a browser<->firmware communication via a websocket (^^^)
• Proof of Concept Phase now done, need to start documenting the approach / architecture
  (async; simple yet composable Arduino-like async loops)
• Keep adding features until it is fully working

Pending patches for discussion

• "Improve code generation": Improve code generation. esp-idf-sys#76 + Fix enums from esp-idf-sys. esp-idf-svc#59

  • Basically introduces a different representation of C-style enums in Rust world
  • I'm more for (-), as the C enums are still not not mapped to Rust enums (good reasons for that) so I'm not sure we are gaining much from this, yet this will be a backwards incompatible change with a huge change surface (we'll break everybody using esp-idf-sys directly)
  • Also introduces sensible Default::default implementations for initializing Wifi. However I'm not very happy with this either, because:
    • We are duplicating code available in ESP-IDF this way (this code is currently in C macros we cannot consume but perhaps we should expose this to Rust via C functions in ESP-IDF)
    • The list is not short. It starts with Wifi, but then Eth, SPI, ... there are lot's of such macros => big code duplication

• GPIO interrupts: add interrupt subscription esp-idf-hal#51

  • Here the patch is delayed as other community members had other ideas how the API should look like, but I don't see them driving their alternative ideas lately. IMO we should continue with the original approach (subscription modelled with a pin type-state + a hidden set of static globals that keep the subscription callback handlers; the globals help us keep the notion of pin zero-sized)

[jessebraham]

espflash

• Opened a (draft) PR adding support for the ESP32-C2:
  • Refactor chip module for less repetition, make more flexible (fewer assumptions)
  • Add support for per-chip flash frequency encodings in the application image

serialport-rs

• Merged additional PRs from community members
• Pretty much ready for a new release, going to do a bit more testing first

miscellaneous

• Tweaks/updates to esp-template, transferred to esp-rs
• Submitted a PR to svd2rust adding CI/regression checks for our SVDs
  • Use the official Espressif SVDs for testing, check additional chips rust-embedded/svd2rust#587
• Upstreamed more SVD patches from esp-pacs, published new SVDs for all chips

[georgik]

Rust training for ESP32-C3 developed by Ferrous Systems

• materials for training: https://espressif-trainings.ferrous-systems.com/
• available as open source: https://github.com/ferrous-systems/espressif-trainings
• next on-line professional training scheduled to week of Embedded World 2022 in Nuremberg - 20th June - open registration

Few notes about limitations discovered during preparation of materials for ESP32-C3

• examples requires nightly-2022-03-10 - later versions of toolchain has problems with compilation - https://github.com/ferrous-systems/espressif-trainings/blob/main/intro/hardware-check/rust-toolchain.toml#L2
• ESP32-C3 with JTAG - stdout is not visible in monitor due to redirection

Finalization 2022-Q1

• esp-rs

Deployment tool (experimental version with limited features)

• new style of multi-platform idf-installer based on Tauri built on GitHub - https://github.com/georgik/idf-installer-tauri/releases
• Vue.js (TypeScript) + Rust
• looks promising and might be able to replace Inno Setup based - Windows only idf-installer
• feature parity with old version + new features backlog - https://github.com/georgik/idf-installer-tauri#feature-parity

[JurajSadel]

Regarding the nightly problem, even the latest nightly should work now ( works on my machine) because ring issue on latest nightly has been resolved.

The actual problem in Ferrous examples was with llvm_asm! macro in rust-embeddedr/riscv crate. The patch from llvm_asm! to asm! is not part of the latest released version so it should be patched with

[patch.crates-io]
riscv = { git = "https://github.com/rust-embedded/riscv", branch = "master"}

to get up-to-date crate.

[bjoernQ]

WiFi Drivers on bare-metal Rust (ESP32C3)

https://github.com/bjoernQ/esp32c3-wifi-rs

Got it working fine so far. It is able to connect to a WiFi access point, get an IP address via DHCP, answers PINGs and sends "Hello World" when connecting to port 4321.

Code is still a mess and needs some re-work - but getting from ugly working code to not so ugly working code shouldn't be that hard.

Next step would be to refactor this and add support for ESP32 (after fixing things mentioned below). If that is successful I guess we can move this to the esp-rs GitHub organization and continue work there.

Steps after that might include

• support Bluetooth LE (including co-ex)
• support esp-now

xtensa-lx-rt

Found out there are some issues in interrupt handling. Refactored the assembly code, created PR.
Looks good so far - I was able to create some basic preempting task scheduler running three tasks on ESP32. (Which we will need for the WiFi drivers)

• Check interrupt handling xtensa-lx-rt#33
• Interesting crash not originating from the HAL but easy to reproduce here esp32-hal#77

When this PR gets merged, there are also changes needed to the PACs (just update the dependency) and ESP-HAL.
PR got merged - will continue on that

[ivmarkov]

WiFi Drivers on bare-metal Rust (ESP32C3)

https://github.com/bjoernQ/esp32c3-wifi-rs

This might well be the greatest ESP32 news (for me at least) for 2022!
Have you been able to stack smol-tcp on top of that?

If we can also get embassy-rs on top of esp-hal, we suddenly have an alternative, pure-Rust stack that only needs a simplistic async HTTP client, server and MQTT client - ideally - implementing the embedded-svc traits. And I can get this guy running on top of it, as most of the code base is against traits from embedded-hal and embedded-svc.

Totally pumped up!

[ivmarkov]

This might well be the greatest ESP32 news (for me at least) for 2022! Have you been able to stack smol-tcp on top of that?

Apparently - yes - you did!

[pedrominatel]

Rust Board

• Soldering done.
• Testing done.
• 16 boards ready for shipment (waiting for DHL pickup).
• 2 boards are dead. Still trying to fix it.
• USB Type-C to Type-C testing done.
• Small label fix and improvements for the next version: v1.1

[JurajSadel]

espflash

• PR created Feature: add subcommand for merging binaries espflash#152
• merges bootloader, partition-table and app binary
• users can specify their own bootloader and/or partition table
• tested in QEMU

[SergioGasquez]

ESP Devcontainer

• Created several tags per esp-idf version and per board
• Dedicated tag for Ferrous Systems' ESP32-C3 training
  • PR created to use devcontainer in the training repo using this image: Add devcontainer std-training#48
• Flashing from the container is possible with Podman on Linux (further test required on macOS and Windows)
• All the image tags are available for linux/amd64 and linux/arm64 except espidf_v4.3.2
• The first time building an ESP Rust project takes 5/10 mins when using macOS and Windows.

esp-idf-sys

• #41, #36 esp-idf-sys#42 commit addressing @N3xed's comments.

[MabezDev]

espflash

• Merged Replace our naive monitor with espmonitor espflash#148 to use espmonitor's addr2line decoding inside espflash's monitor.

esp-idf

• Default to native build with Default to native esp-idf-sys#79 🎉

compiler

• A few internal fixes, to LLVM not yet public.
  • Fix for fixup out of range LLVM error - unlikely that anyone has ran into this, as it only seems to happen on opt-level 1, never the less its been fixed.
  • The spill error from LLVM ERROR: Error while trying to spill A9 from class AR #87 has made some progress, I managed to get a backtrace from LLVM, still need some investigation on the root cause & fix.
• Next release the bare metal esp32s2 target will have its atomic_width_increased from 0, to 32 - Increase atomic width for esp32s2 bare metal target #113

FS issues

• Still working on tracking down the last know bug Can't read files using fs::read and fs::read_to_string #96

[georgik]

Next meeting: 12th April 2022 - 5 pm CEST/GMT+2 (Brno time)

Next Rust toolchain release with Xtensa support - 7th April 2022