Rust on ESP32 STD demo app

A demo STD binary crate for the ESP32[XX] and ESP-IDF, which connects to WiFi, Ethernet, drives a small HTTP server and draws on a LED screen.

Highlights:

• Pure Rust and pure Cargo build! No CMake, no PlatformIO, no C helpers
  • ... via esp-idf-sys and embuild
• Support for Rust STD (threads, console, TCP/IP) safe APIs
  • ... upstreamed and part of the Rust STD library
• New, experimental! Support for asynchronous networking using smol
• Support for running in the Espressif fork of QEMU
• Rust Safe APIs for various ESP-IDF services like WiFi, Ping, Httpd and logging
  • ... via esp-idf-svc (embedded-svc abstractions implemented on top of ESP-IDF)
• NAPT support (Router from the SoftAP to the STA interface). NOTE: In production, do NOT leave the SoftAP interface open (without password)!
• Driving a LED screen with the embedded-graphics Rust crate
  • ... via esp-idf-hal (embedded-hal drivers implemented on top of ESP-IDF)
• (ESP32-S2 only) Blink a LED by loading a pure Rust program onto the RiscV Ultra Low Power CPU

Build

• Install the Rust Espressif compiler toolchain and the Espressif LLVM Clang toolchain
  • This is necessary, because support for the Xtensa architecture (ESP32 / ESP32-S2 / ESP32-S3) is not upstreamed in LLVM yet
• Switch to the esp toolchain from the pre-built binaries: rustup default esp
  • (You can also skip this step and switch to the esp toolchain for the demo crate only by executing rustup override set esp inside the rust-esp32-std-demo directory once you have cloned the demo as per below)
  • NOTE For ESP32-C3 - which runs a RiscV32 chip - you can just use the stock nightly Rust compiler, and a recent, stock Clang (as in Clang 11+)
  • (You can do this by issuing rustup install nightly and then rustup default nightly instead of installing/building the Rust & Clang ESP forks and switching to their esp toolchain as advised above)
• If using the custom Espressif Clang, make sure that you DON'T have a system Clang installed as well, because even if you have the Espressif one first on your $PATH, Bindgen will still pick the system one
  • A workaround that does not require uninstalling the system Clang is to do export LIBCLANG_PATH=<path to the Espressif Clang lib directory> prior to continuing the build process
• cargo install ldproxy
• Clone this repo: git clone https://github.com/ivmarkov/rust-esp32-std-demo
• Enter it: cd rust-esp32-std-demo
• Export two environment variables that would contain the SSID & password of your wireless network:
  • export RUST_ESP32_STD_DEMO_WIFI_SSID=<ssid>
  • export RUST_ESP32_STD_DEMO_WIFI_PASS=<ssid>
• To configure the demo for your particular board, please uncomment the relevant Rust target for your board and comment the others. Alternatively, just append the --target <target> flag to all cargo build lines below.
• Build: cargo build or cargo build --release
  • (Only if you happen to have a TTGO T-Display board): Add ttgo to the --features build flags above (as in cargo build --features ttgo) to be greeted with a Hello Rust! message on the board's LED screen
  • (Only if you happen to have a Waveshare board and a waveshare 4.2" e-paper screen): Add waveshare_epd to the --features build flags above (as in cargo build --features waveshare_epd) to be greeted with a Hello Rust! message on the e-paper screen
  • (Only if you happen to have an ESP32-S2-Kaluga-1 board): Add kaluga to the --features build flags above (as in cargo build --features kaluga) to be greeted with a Hello Rust! message on the board's LED screen
  • (Only if you happen to have a Heltec LoRa 32 board): Add heltec to the --features build flags above (as in cargo build --features heltec) to be greeted with a Hello Rust! message on the board's LED screen
  • (Only if you happen to have an ESP32-S3-USB-OTG): Add esp32s3_usb_otg to the --features build flags above (as in cargo build --features esp32s3_usb_otg) to be greeted with a Hello Rust! message on the board's LED screen
  • (Only if you happen to have an Ethernet-to-SPI board based on the W5500 chip): Add w5500 to the --features build flags above (as in cargo build --features w5500) to have Ethernet connectivity as part of the demo
    • Note that other Ethernet-to-SPI boards might work just fine as well, but you'll have to change the chip from SpiEthDriver::W5500 to whatever chip your SPI board is using, in the demo code itself.
  • (Only if you happen to have an ESP32 board with an onboard IP101 LAN chip and/or a stock ESP32 board connected to an IP101 Ethernet board via RMII): Add ip101 to the --features build flags above (as in cargo build --features ip101) to have Ethernet connectivity as part of the demo
    • Note that other RMII Ethernet boards might work just fine as well, but you'll have to change the chip from RmiiEthDriver::IP101 to whatever chip your board is using, in the demo code itself.
• (Only if you happen to have an ESP32-S2 board and can connect a LED to GPIO Pin 04 and GND): Try accessing http://<dhcp-ip-of-the-board>>/ulp once build is flashed on the MCU

QEMU

• Rather than flashing on the chip, you can now run the demo in QEMU:
  • Clone and then build the Espressif fork of QEMU by following the build instructions
  • Uncomment CONFIG_ETH_USE_OPENETH=y, CONFIG_MBEDTLS_HARDWARE_AES=n, and CONFIG_MBEDTLS_HARDWARE_SHA=n in sdkconfig.defaults.esp32 (it is not enabled by default because this somehow causes issues when compiling for the ESP32S2)
  • Build the app with cargo build --features qemu
  • NOTE: Only ESP32 is supported for the moment, so make sure that the xtensa-esp32-espidf target (the default one) is active in your .cargo/config.toml file (or override with cargo build --features qemu --target xtensa-esp32-espidf)
  • Run it in QEMU by typing ./qemu.sh. NOTE: You might have to change the ESP_QEMU_PATH in that script to point to the build subdirectory of your QEMU Espressif clone

Flash

• cargo install espflash
• espflash /dev/ttyUSB0 target/[xtensa-esp32-espidf|xtensa-esp32s2-espidf|riscv32imc-esp-espidf]/debug/rust-esp32-std-demo
• Replace dev/ttyUSB0 above with the USB port where you've connected the board

NOTE: The above commands do use espflash and NOT cargo espflash, even though both can be installed via Cargo. cargo espflash is essentially espflash but it has some extra superpowers, like the capability to build the project before flashing, or to generate an ESP32 .BIN file from the built .ELF image.

Alternative flashing

• You can also flash with the esptool.py utility which is part of the Espressif toolset
• Use the instructions below only if you have flashed successfully with espflash at least once, or else you might not have a valid bootloader and partition table!
• The instructions below only (re)flash the application image, as the (one and only) factory image starting from 0x10000 in the partition table!
• Install esptool using Python: pip install esptool
• (After each cargo build) Convert the elf image to binary: esptool.py --chip [esp32|esp32s2|esp32c3] elf2image target/xtensa-esp32-espidf/debug/rust-esp32-std-demo
• (After each cargo build) Flash the resulting binary: esptool.py --chip [esp32|esp32s2|esp32c3] -p /dev/ttyUSB0 -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x10000 target/xtensa-esp32-espidf/debug/rust-esp32-std-demo.bin

Monitor

• Once flashed, the board can be connected with any suitable serial monitor, e.g.:

  • ESPMonitor: espmonitor /dev/ttyUSB0 (you need to cargo install espmonitor first)
  • Cargo PIO (this one decodes stack traces!): cargo pio espidf monitor /dev/ttyUSB0 (you need to cargo install cargo-pio first)
    • Please run it from within the rust-esp32-std-demo project directory, or else the built ELF file will not be detected, and the stack traces will not be decoded!
  • Built-in Linux/MacOS screen: screen /dev/ttyUSB0 115200 (use Ctrl+A and then type :quit to stop it)
  • Miniterm: miniterm --raw /dev/ttyUSB0 115200

• If the app starts successfully, it should be listening on the printed IP address from the WiFi connection logs, port 80.

• Open a browser, and navigate to one of these:

  • http://<printed-ip-address>
  • http://<printed-ip-address>/foo?key=value
  • http://<printed-ip-address>/bar
  • http://<printed-ip-address>/ulp (ESP32-S2 only)

• The monitor should output more or less the following:

Hello, world from Rust!
More complex print [foo, bar]
Rust main thread: ...
This is thread number 0 ...
This is thread number 1 ...
This is thread number 2 ...
This is thread number 3 ...
This is thread number 4 ...
About to join the threads. If ESP-IDF was patched successfully, joining will NOT crash
Joins were successful.
I (4761) wifi:wifi driver task: 3ffc1d80, prio:23, stack:6656, core=0
I (4761) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
I (4761) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
I (4771) wifi:wifi firmware version: 3ea4c76
I (4771) wifi:config NVS flash: disabled
I (4781) wifi:config nano formating: disabled
I (4781) wifi:Init dynamic tx buffer num: 32
I (4791) wifi:Init data frame dynamic rx buffer num: 32
I (4791) wifi:Init management frame dynamic rx buffer num: 32
I (4801) wifi:Init management short buffer num: 32
I (4801) wifi:Init static rx buffer size: 1600
I (4811) wifi:Init static rx buffer num: 10
I (4811) wifi:Init dynamic rx buffer num: 32
I (4811) esp_idf_svc::wifi: Driver initialized
I (4821) esp_idf_svc::wifi: Event handlers registered
I (4821) esp_idf_svc::wifi: Initialization complete
I (4831) rust_esp32_std_demo: Wifi created
I (4831) esp_idf_svc::wifi: Setting configuration: Client(ClientConfiguration { ssid: "<your-ssid>", bssid: None, auth_method: WPA2Personal, password: "<your-pass>", ip_conf: Some(DHCP) })
I (4851) esp_idf_svc::wifi: Stopping
I (4861) esp_idf_svc::wifi: Disconnect requested
I (4861) esp_idf_svc::wifi: Stop requested
I (4871) esp_idf_svc::wifi: About to wait for status
I (4871) esp_idf_svc::wifi: Providing status: Status(Stopped, Stopped)
I (4881) esp_idf_svc::wifi: Waiting for status done - success
I (4881) esp_idf_svc::wifi: Stopped
I (4891) esp_idf_svc::wifi: Wifi mode STA set
I (4891) esp_idf_svc::wifi: Setting STA configuration: ClientConfiguration { ssid: "<your-ssid>", bssid: None, auth_method: WPA2Personal, password: "<your-pass>", ip_conf: Some(DHCP) }
I (4911) esp_idf_svc::wifi: Setting STA IP configuration: DHCP
I (4921) esp_idf_svc::wifi: STA netif allocated: 0x3ffc685c
I (4921) esp_idf_svc::wifi: STA IP configuration done
I (4931) esp_idf_svc::wifi: STA configuration done
I (4931) esp_idf_svc::wifi: Starting with status: Status(Starting, Stopped)
I (4941) esp_idf_svc::wifi: Status is of operating type, starting
I (5041) phy: phy_version: 4180, cb3948e, Sep 12 2019, 16:39:13, 0, 0
I (5041) wifi:mode : sta (f0:08:d1:77:68:f0)
I (5041) esp_idf_svc::wifi: Got wifi event: 2
I (5051) esp_idf_svc::wifi: Recconecting
I (5051) esp_idf_svc::wifi: Start requested
I (5051) esp_idf_svc::wifi: Set status: Status(Started(Connecting), Stopped)
I (5061) esp_idf_svc::wifi: About to wait for status with timeout 10s
I (5071) esp_idf_svc::wifi: Wifi event 2 handled
I (5091) esp_idf_svc::wifi: Providing status: Status(Started(Connecting), Stopped)
I (5171) wifi:new:<1,1>, old:<1,0>, ap:<255,255>, sta:<1,1>, prof:1
I (5941) wifi:state: init -> auth (b0)
I (5951) esp_idf_svc::wifi: Providing status: Status(Started(Connecting), Stopped)
I (5951) wifi:state: auth -> assoc (0)
I (5961) wifi:state: assoc -> run (10)
I (5981) wifi:connected with muci, aid = 1, channel 1, 40U, bssid = 08:55:31:2e:c3:cf
I (5981) wifi:security: WPA2-PSK, phy: bgn, rssi: -54
I (5981) wifi:pm start, type: 1

I (5991) esp_idf_svc::wifi: Got wifi event: 4
I (5991) esp_idf_svc::wifi: Set status: Status(Started(Connected(Waiting)), Stopped)
I (6001) esp_idf_svc::wifi: Wifi event 4 handled
I (6011) wifi:AP's beacon interval = 102400 us, DTIM period = 1
I (6451) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Waiting)), Stopped)
I (6951) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Waiting)), Stopped)
I (7451) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Waiting)), Stopped)
I (7951) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Waiting)), Stopped)
I (8221) esp_idf_svc::wifi: Got IP event: 0
I (8221) esp_idf_svc::wifi: Set status: Status(Started(Connected(Done(ClientSettings { ip: 192.168.10.155, subnet: Subnet { gateway: 192.168.10.1, mask: Mask(24) }, dns: None, secondary_dns: None }))), Stopped)
I (8231) esp_idf_svc::wifi: IP event 0 handled
I (8241) esp_netif_handlers: staSTA netif allocated:  ip: 192.168.10.155, mask: 255.255.255.0, gw: 192.168.10.1
I (8451) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Done(ClientSettings { ip: 192.168.10.155, subnet: Subnet { gateway: 192.168.10.1, mask: Mask(24) }, dns: None, secondary_dns: None }))), Stopped)
I (8461) esp_idf_svc::wifi: Waiting for status done - success
I (8461) esp_idf_svc::wifi: Started
I (8471) esp_idf_svc::wifi: Configuration set
I (8471) rust_esp32_std_demo: Wifi configuration set, about to get status
I (8481) esp_idf_svc::wifi: Providing status: Status(Started(Connected(Done(ClientSettings { ip: 192.168.10.155, subnet: Subnet { gateway: 192.168.10.1, mask: Mask(24) }, dns: None, secondary_dns: None }))), Stopped)
I (8501) rust_esp32_std_demo: Wifi connected, about to do some pings
I (8511) esp_idf_svc::ping: About to run a summary ping 192.168.10.1 with configuration Configuration { count: 5, interval: 1s, timeout: 1s, data_size: 56, tos: 0 }
I (8521) esp_idf_svc::ping: Ping session established, got handle 0x3ffc767c
I (8531) esp_idf_svc::ping: Ping session started
I (8531) esp_idf_svc::ping: Waiting for the ping session to complete
I (8541) esp_idf_svc::ping: Ping success callback invoked
I (8551) esp_idf_svc::ping: From 192.168.10.1 icmp_seq=1 ttl=64 time=14ms bytes=64
I (9531) esp_idf_svc::ping: Ping success callback invoked
I (9531) esp_idf_svc::ping: From 192.168.10.1 icmp_seq=2 ttl=64 time=1ms bytes=64
I (10531) esp_idf_svc::ping: Ping success callback invoked
I (10531) esp_idf_svc::ping: From 192.168.10.1 icmp_seq=3 ttl=64 time=2ms bytes=64
I (11531) esp_idf_svc::ping: Ping success callback invoked
I (11531) esp_idf_svc::ping: From 192.168.10.1 icmp_seq=4 ttl=64 time=0ms bytes=64
I (12531) esp_idf_svc::ping: Ping success callback invoked
I (12531) esp_idf_svc::ping: From 192.168.10.1 icmp_seq=5 ttl=64 time=1ms bytes=64
I (13531) esp_idf_svc::ping: Ping end callback invoked
I (13531) esp_idf_svc::ping: 5 packets transmitted, 5 received, time 18ms
I (13531) esp_idf_svc::ping: Ping session stopped
I (13531) esp_idf_svc::ping: Ping session 0x3ffc767c removed
I (13541) rust_esp32_std_demo: Pinging done
I (13551) esp_idf_svc::httpd: Started Httpd IDF server with config Configuration { http_port: 80, https_port: 443 }
I (13561) esp_idf_svc::httpd: Registered Httpd IDF server handler Get for URI "/"
I (13561) esp_idf_svc::httpd: Registered Httpd IDF server handler Get for URI "/foo"
I (13571) esp_idf_svc::httpd: Registered Httpd IDF server handler Get for URI "/bar"