Arduino and PlatformIO use

NobroRTOS Core is packaged as a header-only Arduino library. Scheduler<N> owns a fixed copy of exactly N task descriptors, periodic release timestamps, one priority-to-task map, and one ready bitmap. It allocates no memory and creates no hidden task stacks.

Define a workload

#include <NobroRTOSCore.h>

using nobro::core::Scheduler;
using nobro::core::Task;

void sample(void *context) {
    // Return before the declared WCET expires.
}

Scheduler<1> scheduler;

void setup() {
    static const Task tasks[] = {
        Task::periodic(1, 0, 1000, 1000, 40, sample),
    };
    const nobro::core::AdmissionResult result = scheduler.begin(tasks, micros());
    if (result != nobro::core::ADMITTED) {
        // Keep the application fail-closed or report the exact result.
    }
}

void loop() {
    scheduler.releaseDue(micros());
    scheduler.runReady();
    yield();
}

Priorities are unique values from 0 through 31; lower values run first. A periodic interval, finish deadline, phase, and WCET must remain inside the wrap-safe half of the 32-bit microsecond clock. Admission checks aggregate periodic utilization and apply a conservative fixed-priority, run-to-completion response-time test with one lower-priority blocking job.

Event tasks use Task::event(...) and are released with markReady(index) or markReadyById(id). They have no invented arrival rate, so the application must separately bound the source's burst/rate and include that interference in its measured WCET/deadline design. runReady() defaults to at most N dispatches per call, preventing a callback that republishes work from trapping the outer loop indefinitely.

API at a glance

API	Purpose
`Task::periodic(...)`	Declare a periodic callback with priority, period, finish deadline, WCET, optional context, and optional phase
`Task::event(...)`	Declare work released by an application event
`scheduler.begin(tasks, now)`	Copy and admit the fixed task table
`scheduler.releaseDue(now)`	Release every periodic task due at this time while preserving phase
`scheduler.markReady(index)`	Release a task by fixed index
`scheduler.markReadyById(id)`	Release a task by stable application ID
`scheduler.takeNext(index)`	Take the highest-priority ready task without calling it
`scheduler.runNext()`	Run one highest-priority ready callback
`scheduler.runReady(limit)`	Run a bounded number of ready callbacks
`scheduler.nextRelease(now, out)`	Report the next periodic release for a board-owned idle policy

begin() returns an exact AdmissionResult. Applications can report DUPLICATE_ID, DUPLICATE_PRIORITY, INVALID_TIMING, UTILIZATION_EXCEEDED, or DEADLINE_MISS instead of entering an uncertain schedule.

Interrupt ownership

The public scheduler does not disable interrupts or assume a board-specific atomic implementation. Call scheduler-mutating methods from one owner. If an ISR releases an event, publish it through an atomic board flag or protect the ready-state update with that board's correct critical section before calling markReady from the scheduler owner. This keeps the portable package honest on 8-bit as well as 32-bit boards.

Install

For Arduino IDE, download the tagged source archive, choose Sketch > Include Library > Add .ZIP Library..., then open File > Examples > NobroRTOSCore > BlinkCore. Library Manager installation becomes available after the release is accepted into Arduino's index.

For PlatformIO, use the registry package after publication or pin the exact Git tag:

[env:example]
platform = atmelavr
board = uno
framework = arduino
lib_deps = https://github.com/dunknowcoding/NobroRTOS.git#v1.0.1

library.properties and library.json intentionally share the Cargo workspace version. The package metadata gate rejects version, license, header, example, or archive drift before release.

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