Embedded Working Group Meeting 2022-09-06

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• Meetings: Tuesday 8pm Europe/Berlin time
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• Today's date: 2022-09-06
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Attendance

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• adamgreig
• dirbaio
• cr1901
• newAM
• therealprof
• ChristofPetig
• jannic
• eldruin

Agenda

• Announcements
• Embedded HAL
  • critical-section std poisoning?
    • https://github.com/rust-embedded/critical-section/pull/26
      • Discussed in depth.
      • We should specify with's behaviour on unwind, and this seems a sensible behaviour
      • Need to check codegen doesn't suffer for typical no-std uses
      • Don't think any changes needed to acquire/release/CriticalSection preconditions
  • c-s bloat on msp430
    • no updates this week
  • spi traits on linux
    • also no updates this week
  • Split nb
    • https://github.com/rust-embedded/embedded-hal/pull/394
    • updated to have embedded-can 0.4 and embedded-hal-nb 1.0
    • move embedded-hal to a subdir now that the split is going to be permanent?
      • Yes (note, no workspace)

Last Week's Minutes

• Announcements

  • Friday showcase happened on Twitter https://twitter.com/rustembedded/status/1563156111829913600
  • We have published the first releases of esp-hal, no_std HALs for ESP32, ESP32-C3, ESP32-S2, and ESP32-S3
    • https://github.com/esp-rs/esp-hal
  • embassy-futures released, more embassy crate releases coming soon in the following days
    • https://crates.io/crates/embassy-futures

• Embedded HAL

  • critical-section bloat on msp430/cortex-m?
    • cr1901 continues to investigate
  • SPI traits on Linux?
    • https://github.com/rust-embedded/linux-embedded-hal/issues/87
    • hard to work out how to comply with new e-h 1.0 traits using spidev, which handles CS and bus sharing internally
    • might be best to buffer writes in a transaction and send them on read/flush/end-of-transaction
    • not fully compliant but better for many use cases
    • the spibus impl will also be mostly lies, but again there might not be much we can do except document it carefully
  • New I2C trait https://github.com/rust-embedded/embedded-hal/pull/392
    • No updates this week
  • Split nb https://github.com/rust-embedded/embedded-hal/pull/394
    • Will rename embedded-hal-can folder to embedded-can and release at version 0.4
    • Will make embedded-hal-nb version 1.0 but hold off releasing for right now
  • New bare-metal?
    • Wait while msp430 and svd2rust stuff gets shaken out
  • Shared singleton macro?
    • Probably prefer static_cell, could even deprecate singleton for c-m 0.8