---
title: "Subsystems"
canonical_url: https://developer.repebble.com/pebbleos/docs/subsystems/
last_updated: 2026-10-21
sdk_version: 4.33.1
---
# Subsystems

Source: https://developer.repebble.com/pebbleos/docs/subsystems/

Subsystems are self-contained OS components under `subsys/`, each with its public API in `include/pbl/<name>/`. Most follow the same pattern: users declare what they need next to their own code, the subsystem collects it at link time, and a Kconfig option selects the backend.

- [Bluetooth](https://developer.repebble.com/pebbleos/docs/subsystems/bluetooth.md)
- [CRC](https://developer.repebble.com/pebbleos/docs/subsystems/crc.md)
- [Input](https://developer.repebble.com/pebbleos/docs/subsystems/input.md)
- [Logging](https://developer.repebble.com/pebbleos/docs/subsystems/logging.md)
- [Shell](https://developer.repebble.com/pebbleos/docs/subsystems/shell.md)
- [Task watchdog](https://developer.repebble.com/pebbleos/docs/subsystems/task_watchdog.md)

The [API reference](https://developer.repebble.com/pebbleos/apidoc/d4/d31/group__subsys.html) documents every subsystem’s interface.

Generated from PebbleOS [3a7b71785](https://github.com/coredevices/pebbleos/commit/3a7b71785fd439666c4a8bc116f561140e8dec01). This page is maintained in the pebbleos repository: [docs/subsystems/index.md](https://github.com/coredevices/pebbleos/blob/3a7b71785fd439666c4a8bc116f561140e8dec01/docs/subsystems/index.md).