kernel-basics

name	kernel-basics
description	Essential Zephyr RTOS kernel services. Covers thread lifecycle and priority, the logging subsystem for diagnostics, and the interactive shell for real-time hardware inspection and debugging. Trigger when writing application flows, adding logging to modules, or creating interactive CLI commands.

Zephyr Kernel Basics

Master the essential services that bring your Zephyr application to life.

Core Workflows

1. Threads & Scheduling

Create and manage multi-threaded application flows.

• Reference: threads.md
• Key Tools: K_THREAD_DEFINE, k_sleep, k_yield, Priorities.

2. Logging & Diagnostics

Implement layered logging for better observability and troubleshooting.

• Reference: logging.md
• Key Tools: LOG_MODULE_REGISTER, LOG_INF, LOG_ERR, Dynamic Filtering.

3. Interactive Shell (CLI)

Build powerful command-line interfaces for hardware and software inspection.

• Reference: shell.md
• Key Tools: SHELL_CMD_REGISTER, SHELL_STATIC_SUBCMD_SET_CREATE.

Quick Start (Logging)

#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(my_app, CONFIG_APP_LOG_LEVEL);

void my_fn(void) {
    LOG_INF("Hello from Zephyr!");
}

Quick Start (Threads)

K_THREAD_DEFINE(worker_tid, 1024, worker_fn, NULL, NULL, NULL, 5, 0, 0);

Automation Tools

• log_summary.py: Parse Zephyr runtime logs and summarize counts by level/module.

Examples & Templates

• shell_command_template.c: Starter command set for shell registration patterns.

Validation Checklist

• Log output includes module tag and expected log level filtering.
• At least one worker thread starts and runs at the intended priority.
• Shell command registration appears in help output and executes without faults.
• No blocking or mutex misuse appears in ISR-context paths.

Resources

• References:
  • threads.md: Configuration and creation of kernel threads.
  • logging.md: Log levels, modules, and backends.
  • shell.md: Interactive command registration and subcommands.
• Scripts:
  • log_summary.py: Runtime log summarizer for quick diagnostics.
• Assets:
  • shell_command_template.c: Shell command registration template.