当前文档版本为 v0.8.0，您可以访问当前页面的开发中版本以获取最近可能的更新。

Driver: Power Management¶

1 功能概述¶

本文主要介绍PAN1080 EVB板PM中进入低功耗前后的回调函数使用说明。

2 环境要求¶

PAN1080 EVB 一块
USB-TypeC 线一条（用于供电和查看串口打印 Log）
硬件接线：
- 使用 USB 线，将 PC USB 与 EVB USB-TypeC（USB->UART）相连
- 根据 EVB 核心板芯片的封装不同，使用杜邦线将 EVB 底板上的:
  - TX0 与 P00 相连， RX0 与 P01 相连（若 EVB 板芯片为 QFN32 或 LQFP64 封装）
  - TX0 与 P30 相连， RX0 与 P31 相连（若 EVB 板芯片为 QFN48 封装）
PC 软件: 串口调试助手（UartAssist）或终端工具（SecureCRT），波特率921600

3 编译和烧录¶

例程位置：zephyr\samples_panchip\drivers\pm

使用 ZAL 工具可以对其进行编译、烧录、打开 VS Code 调试等操作。关于 ZAL 工具的详细介绍请参考：Zephyr APP Launcher 工具介绍。

4 演示说明¶

*** Booting Zephyr OS build zephyr-v2.7.0-667-gae423d90e384  ***
Remained loop count: 1
Wake up from cpu idle
pm entry hook, state=1
pm exit hook, state=1
Wake up from runtime-idle
pm entry hook, state=2
pm exit hook, state=2
Wake up from suspend-to-idle

Remained loop count: 0
Wake up from cpu idle
pm entry hook, state=1
pm exit hook, state=1
Wake up from runtime-idle
pm entry hook, state=2
pm exit hook, state=2
Wake up from suspend-to-idle

Expect wake up from suspend-to-ram retention:0

pm entry hook, state=4
*** Booting Zephyr OS build zephyr-v2.7.0-667-gae423d90e384  ***
Remained loop count: 1
Wake up from cpu idle
pm entry hook, state=1
pm exit hook, state=1
Wake up from runtime-idle
pm entry hook, state=2
pm exit hook, state=2
Wake up from suspend-to-idle

Remained loop count: 0
Wake up from cpu idle
pm entry hook, state=1
pm exit hook, state=1
Wake up from runtime-idle
pm entry hook, state=2
pm exit hook, state=2
Wake up from suspend-to-idle

Expected wake up from soft-off retention:1

pm entry hook, state=6

上电后打印如上数据，该sample未和蓝牙deepsleep功能绑定，暂时只用于pm_notifier_register演示，会进入MCU Sleep，deepsleep，standby mode1，standby mode0模式。

standby mode会使SOC复位，其中mode1模式会保持ram数据不掉电，因此通过ram_retention_flag来区分standby 模式。

该例程依次运行run mode–>deepsleep mode–>standby mode1–>reset–>run mode–>deepsleep mode–>standby mode0

5 开发者说明¶

低功耗模式说明¶

具体流程请参考:

PAN108x User Manual

进入低功耗的时机¶

&cpu0 {
	cpu-power-states = <&state0 &state1 &state2 &state3>;
};

&state0 {
	compatible = "zephyr,power-state";
	power-state-name = "runtime-idle";
	min-residency-us = <200000>;
	exit-latency-us = <32>;
};

&state1 {
	compatible = "zephyr,power-state";
	power-state-name = "suspend-to-idle";
	min-residency-us = <500000>;
	exit-latency-us = <32>;
};

&state2 {
	compatible = "zephyr,power-state";
	power-state-name = "suspend-to-ram";
	min-residency-us = <800000>;
	exit-latency-us = <32>;
};

&state3 {
	compatible = "zephyr,power-state";
	power-state-name = "soft-off";
	min-residency-us = <1500000>;
	exit-latency-us = <32>;
};

以该参数来说明：

cpu0有四种低功耗状态，分别为

state0:runtime-idle（run mode）
state1:suspend-to-idle（deepsleep mode）
state2:suspend-to-ram（standby mode1）
state3:soft-off（standby mode0）

如果idle时间满足以下条件：

if (time_to_next_scheduled_event >= (state.min_residency_us + state.exit_latency))) {
return state
}

则进入相应的state。

进入低功耗前后的回调函数¶

static void notify_pm_state_entry(enum pm_state state)
{
	printk("pm entry\n");
}

static void notify_pm_state_exit(enum pm_state state)
{
	printk("pm exit\n");
}

static struct pm_notifier notifier = {
	.state_entry = notify_pm_state_entry,	//进入低功耗前的回调函数
	.state_exit = notify_pm_state_exit,		//从低功耗出来后的回调函数
};

/** 注册低功耗回调函数*/
pm_notifier_register(&notifier);

/** 撤销注册低功耗回调函数*/
pm_notifier_unregister(&notifier);

6 RAM/Flash资源使用情况¶

Memory region         Used Size  Region Size  %age Used
FLASH:       21540 B       256 KB      8.22%
SRAM:        6040 B        64 KB      9.22%