Accessing Hardware in Rust

A deep dive into hardware access patterns in Rust for bare-metal embedded systems. Covers three hardware access mechanisms: I/O ports, system/co-processor registers, and memory-mapped I/O (MMIO). Explains why volatile writes are required for MMIO, why creating Rust references to MMIO addresses is unsound, and how bitfields within registers are typically handled. Compares four major Rust MMIO abstraction crates — svd2rust, tock-registers, safe-mmio, and derive-mmio — evaluating each on API ergonomics, documentation discoverability, soundness, and AArch64 hypervisor compatibility. Also highlights the importance of running cargo doc to validate the developer experience of generated documentation.