Show HN: TinyOS – A minimalist RTOS for Cortex-M written in C

Summary

TinyOS — Ultra-Lightweight RTOS for IoT An ultra-lightweight real-time operating system for resource-constrained IoT and embedded devices. Kernel footprint under 10 KB, 2 KB minimum RAM, preemptive priority-based scheduling. Category Details Kernel Preemptive priority-based scheduling (256 levels), round-robin within same priority, O(1) priority lookup via bitmap, priority inheritance Synchronization Mutex (with priority inheritance), semaphore, condition variable, event groups, message queues Software Timers One-shot and auto-reload, millisecond precision, period change at runtime Memory Fixed-block pool allocator, stack overflow detection, per-task high-water mark Shell VT100 interactive shell — 19 built-in commands, command history (↑↓), tab completion, full line editor File System Lightweight block-device FS, POSIX-like API, wear levelling, power-fail safe Network Ethernet, IPv4, ICMP, UDP, TCP, HTTP client/server, DNS TLS / DTLS TLS 1.2/1.3 over TCP, DTLS 1.2 over UDP (mbedTLS backend) MQTT Full MQTT 3.1.1 — QoS 0/1/2 with in-flight retry table, offline queue, auto-reconnect with exponential back-off CoAP RFC 7252 compliant client/server, observe pattern OTA A/B partition firmware updates, CRC32 verification, rollback Watchdog Hardware and software watchdog, per-task timeout monitoring Power Idle / Sleep / Deep-sleep modes, tickless idle, CPU frequency scaling Security MPU-based memory protection, secure boot support Architecture Examples ARM Cortex-M (M0/M0+/M3/M4/M7) STM32, nRF52, Raspberry Pi Pico RISC-V (RV32I) ESP32-C3 AVR (experimental) ATmega Prerequisites: gcc-arm-none-eabi make example-blink # LED blink make example-shell # Interactive shell over UART make example-mqtt # MQTT publish/subscribe make example-iot # Multi-sensor IoT node make size # Binary size report Minimal task example: #include "tinyos.h" void my_task(void *param) { while (1) { /* work */ os_task_delay_ms(100); } } int main(void) { tcb_t task; os_init(); os_task_create(&task, "my_task"...