microtimer

Software timer manager for embedded systems.

C99 | Zero dependencies | Zero allocations | Oneshot + Periodic | Portable

Why microtimer?

Embedded main loops often contain repeated timing checks:

if (now - last_blink > 500) { toggle_led(); last_blink = now; }
if (now - last_send > 5000) { send_telemetry(); last_send = now; }
if (now - last_check > 1000) { check_sensors(); last_check = now; }

microtimer replaces this with registered timers and a single tick path:

mtimer_create(&tm, "blink",   500,  MTIMER_PERIODIC, on_blink, NULL);
mtimer_create(&tm, "send",    5000, MTIMER_PERIODIC, on_send, NULL);
mtimer_create(&tm, "timeout", 3000, MTIMER_ONESHOT,  on_timeout, NULL);

while (1) {
    mtimer_tick(&tm);
}

Features

• Oneshot timers that auto-stop after firing.
• Periodic timers with drift correction.
• Pause/resume with remaining-time preservation.
• Dynamic interval changes at runtime.
• Slot reuse through destroy/create.
• Named timer lookup for diagnostics and shell commands.
• Per-timer and global fire counters.

Build and Test

Requirements:

• C99 compiler (gcc or clang)
• make

Run tests:

# clone microtest next to this repository root
# expected path: ../microtest/include
make -C tests

Public API

Key functions:

• mtimer_init
• mtimer_create, mtimer_destroy
• mtimer_start, mtimer_stop, mtimer_pause, mtimer_resume
• mtimer_set_interval
• mtimer_tick
• mtimer_count, mtimer_find, mtimer_remaining

See include/mtimer.h for full API details.

Repository Layout

• include/mtimer.h - public API
• src/mtimer.c - implementation
• tests/test_all.c - unit tests
• docs/DESIGN.md - design rationale

Ecosystem

• microhealth
• microwdt
• microres
• microsh

Configuration

• MTIMER_MAX_TIMERS (default: 8)

Contributing

See CONTRIBUTING.md.

Changelog

See CHANGELOG.md.

License

MIT - see LICENSE.