Embassy
An embedded Rust framework that replaces RTOS threads with async/await.
The premise is that most of what firmware does is wait — for an interrupt, a timer, a byte on the UART. An RTOS gives every waiting task its own stack. In Embassy each task is a Future that the compiler turns into a state machine of exactly known size, and an executor polls them in turn. When nothing is ready the core drops into WFI until the next interrupt, so low-power behaviour falls out of the design instead of being hand-written sleep logic.
Started around 2020 by Dario Nieuwenhuis, the project ships its own HALs for STM32, Nordic's nRF parts and the Raspberry Pi RP2040, along with networking and USB stacks. It is dual-licensed MIT/Apache, as is customary in Rust land.