当前页面为 开发中 版本，查看特定版本的文档，请在页面左下角的下拉菜单中进行选择。

Subsys: Settings

1 功能概述

Zephyr 提供了一个名为 Settings 的键值对（Key-Value Pair）字符串数据存储子系统，其实现基于 NVS 或文件系统提供的底层接口。本例程演示 Settings 相关接口的基本用法，包括 NVS Backend 与 Runtime Backend。

2 环境要求

• Board: pan108xxa1_evb / pan108xxa3_evb / pan108xxb1_evb / pan108xxb5_evb

  • UART: 将 P00 与 TX0 引脚接在一起，P01 与 RX0 引脚接在一起，在 PC 上打开终端工具（如 SecureCRT），波特率设置为 921600

3 编译和烧录

例程位置：zephyr\samples_panchip\subsys\settings

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

程序下载后，在终端工具（SecureCRT）中可以看到如下的 Log 打印信息：

Try to load HW calibration data.. DONE.
- Chip Type         : 0x80
- Chip CP Version   : None
- Chip FT Version   : 5
- Chip MAC Address  : D0000C029382
- Chip Flash UID    : 31373237300A44594330FFFFFFFFFFFF
- Chip Flash Size   : 1024 KB
*** Booting Zephyr OS build zephyr-v2.7.0-1633-gc485e109  ***

*** Settings usage example ***

settings subsys initialization: OK.
subtree <alpha> handler registered: OK
subtree <alpha/beta> has static handler

##############
# iteration 0
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 42
<alpha/length/1> = 58
<alpha/angle/1> = 18
<alpha/beta/source> =
<alpha/beta/voltage> = -3450
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> =
<alpha/beta/voltage> = -3475
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 59
  direct.length_2 = 41

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 18
save <gamma> key directly: OK.

##############
# iteration 1
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 41
<alpha/length/1> = 59
<alpha/angle/1> = 19
<alpha/beta/source> = a
<alpha/beta/voltage> = -3475
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> = a
<alpha/beta/voltage> = -3500
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 60
  direct.length_2 = 40

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 19
save <gamma> key directly: OK.

##############
# iteration 2
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 40
<alpha/length/1> = 60
<alpha/angle/1> = 20
<alpha/beta/source> = ab
<alpha/beta/voltage> = -3500
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> = ab
<alpha/beta/voltage> = -3525
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 61
  direct.length_2 = 39

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 20
save <gamma> key directly: OK.

##############
# iteration 3
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 39
<alpha/length/1> = 61
<alpha/angle/1> = 21
<alpha/beta/source> = abc
<alpha/beta/voltage> = -3525
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> = abc
<alpha/beta/voltage> = -3550
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 62
  direct.length_2 = 38

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 21
save <gamma> key directly: OK.

##############
# iteration 4
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 38
<alpha/length/1> = 62
<alpha/angle/1> = 22
<alpha/beta/source> = abcd
<alpha/beta/voltage> = -3550
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> = abcd
<alpha/beta/voltage> = -3575
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 63
  direct.length_2 = 37

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 22
save <gamma> key directly: OK.

##############
# iteration 5
##############

=================================================
basic load and save using registered handlers

load all key-value pairs using registered handlers
<alpha/length/2> = 37
<alpha/length/1> = 63
<alpha/angle/1> = 23
<alpha/beta/source> is not compatible with the application
<alpha/beta/voltage> = -3575
loading all settings under <beta> handler is done
loading all settings under <alpha> handler is done

save <alpha/beta/voltage> key directly: OK.

load <alpha/beta> key-value pairs using registered handlers
<alpha/beta/source> is not compatible with the application
<alpha/beta/voltage> = -3600
loading all settings under <beta> handler is done

save all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

load all key-value pairs using registered handlers
export keys under <beta> handler
export keys under <alpha> handler

=================================================
loading subtree to destination provided by the caller

direct load: <alpha/length>
direct load: <alpha/length/2>
direct load: <alpha/length/1>
  direct.length = 100
  direct.length_1 = 64
  direct.length_2 = 36

=================================================
Delete a key-value pair

immediate load: OK.
  <alpha/length> value exist in the storage
delete <alpha/length>: OK.
  Can't to load the <alpha/length> value as expected

=================================================
Service a key-value pair without dedicated handlers

immediate load: OK.
<gamma> = 23
save <gamma> key directly: OK.

=================================================
Inject the value to the setting destination in runtime

<alpha/beta/source> = RT
injected <alpha/beta/source>: OK.
  The settings destination off the key <alpha/beta/source> has got value: "RT"


=================================================
Read a value from the setting destination in runtime

fetched <alpha/beta/source>: OK.
  String value "rtos" was retrieved from the settings destination off the key <alpha/beta/source>

*** THE END  ***

5 开发说明

1. 本例程演示的 Settings 功能需要开启如下的 Kconfig 选项：

   CONFIG_FLASH=y
   CONFIG_FLASH_PAGE_LAYOUT=y
   CONFIG_FLASH_MAP=y
   
   CONFIG_SETTINGS=y
   CONFIG_SETTINGS_RUNTIME=y
   CONFIG_NVS=y
   CONFIG_SETTINGS_NVS=y
   

2. settings 相关接口定义及介绍请参考：zephyr\include\settings\settings.h

6 RAM/Flash资源使用情况

Memory region         Used Size  Region Size  %age Used
FLASH:       26592 B       384 KB      6.76%
SRAM:        4344 B        64 KB      6.63%