> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/man/man4/atrtc.4.md).

# atrtc.4

`atrtc` — AT 实时时钟（RTC）驱动

## 名称

`atrtc`

## 概要

此驱动是 i386/amd64 内核的必需部分。

以下可调参数可从 [loader(8)](/man/man8/loader.8.md) 设置：

**hint.atrtc.X.clock** 控制事件计时器功能支持。设为 0 则禁用。默认值为 1。

**hw\.atrtc.enabled** 强制启用或禁用设备。设为 0 禁用，设为 1 启用，绕过任何平台配置提示。默认值为 -1（自动检测）。

## 描述

此驱动使用 RTC 硬件为内核提供 1 秒分辨率的当日时钟和一个事件计时器。此硬件使用 32768Hz 基础频率推进当日时钟并生成周期性中断。中断可由固定数量的频率生成，范围从 2Hz 到 8192Hz，通过将基础频率除以支持的 2 的幂除数之一获得。

该驱动提供的事件计时器与 CPU 电源状态无关。

## 参见

[apic(4)](/man/man4/apic.4.md), [attimer(4)](/man/man4/attimer.4.md), [eventtimers(4)](/man/man4/eventtimers.4.md), [hpet(4)](/man/man4/hpet.4.md)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://book.bsdcn.org/man/man4/atrtc.4.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.