【经验】地平线X3M开发板上AP6212模组的Wi-Fi功能使用方法

地平线X3M开发板上的AP6212模组是一种低成本、低功耗的模组，集成有WiFi，蓝牙和FM功能，广泛应用到智能手机和便携式设备中。本文主要介绍AP6212 WiFi功能的使用方法。

1. 确认WiFi的工作状态

开发板上电默认工作在STATION模式下，可以通过 ifconfig -a 命令查看到 wlan0 的网络节点：

root@x3sdbx3-samsung2G-3200:~# ifconfig -a
wlan0     Link encap:Ethernet  HWaddr 70:4a:0e:13:69:aa  
         BROADCAST MULTICAST  MTU:1500  Metric:1
         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

2. 联网测试

运行 wifi_connect [ssid] [password] 连接热点联网。运行结果如下所示。

root@x3sdbx3-samsung2G-3200:~# wifi_connect "WiFi-Test" "12345678"udhcpc: started, v1.31.0
udhcpc: sending discover
udhcpc: sending select for 192.168.137.26
udhcpc: lease of 192.168.137.26 obtained, lease time 604800/userdata/udhcpc.d/50default: Adding DNS 192.168.137.1

root@x3sdbx3-samsung2G-3200:~#  ping www.horizon.ai
PING www.horizon.ai (47.92.42.221): 56 data bytes64 bytes from 47.92.42.221: seq=0 ttl=88 time=204.797 ms64 bytes from 47.92.42.221: seq=1 ttl=88 time=126.666 ms64 bytes from 47.92.42.221: seq=4 ttl=88 time=197.004 ms64 bytes from 47.92.42.221: seq=5 ttl=88 time=118.345 ms
--- www.horizon.ai ping statistics ---6 packets transmitted, 4 packets received, 33% packet loss
round-trip min/avg/max = 118.345/161.703/204.797 ms

3. 切换Wi-Fi的工作模式

AP6212支持AP和STATION两种模式，开发板上电默认工作在STATION模式下。在sdk中提供wifi_init程序来对wifi的工作模式进行切换。

(1). 设置AP6212工作在AP模式，请执行wifi_init ap命令设置模式，运行过程如下所示，在结束时出现wlan0: AP-ENABLED说明设置成功，生成的热点名为 sunrise，没有设置密码：

root@x3sdbx3-samsung2G-3200:~# wifi_init ap
Initialize wlan0 to ap mode[   81.631181] x3sdbx3-samsung2G-3200:unkown: Untracked pid 1949 killed by signal 9[   81.672070] x3sdbx3-samsung2G-3200:unkown: Untracked pid 1913 killed by signal 9[   83.672208] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
Configuration file: /etc/hostapd.conf
Failed to create interface mon.wlan0: -95 (Operation not supported)wlan0: Could not connect to kernel driver
Using interface wlan0 with hwaddr 08:e9:f6:af:18:26 and ssid "sunrise"[   83.800766] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan0: interface state UNINITIALIZED->ENABLED
wlan0: AP-ENABLED
Finish initialize wlan0 to ap mode

(2). 设置AP6212工作在STATION模式，请执行 wifi_init sta 命令设置模式，运行过程如下所示，可以通过ps命令查看 wpa_supplicant 和 udhcpc是否在运行来确定切换是否成功，并进行联网测试。

root@x3sdbx3-samsung2G-3200:~# wifi_init sta
Initialize wlan0 to station mode[  115.605035] x3sdbx3-samsung2G-3200:unkown: Untracked pid 1972 killed by signal 9[  115.652050] x3sdbx3-samsung2G-3200:unkown: Untracked pid 1974 killed by signal 9[  118.104320] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
Finish initialize wlan0 to station mode

root@x3sdbx3-samsung2G-3200:~# ps
2150 root   20   0 10248 S    wpa_supplicant -D nl80211 -i wlan0 -c /tmp/wpa_supplicant.conf -B 

2179 root   20   0  3252 S    udhcpc -i wlan0 -s /usr/share/udhcpc/default.script

当前配置的热点是没有设置密码的，如果需要添加密码，请修改 /etc/hostapd.conf 为如下内容后，重新执行 wifi_init ap。

interface=wlan0driver=nl80211ctrl_interface=/var/run/hostapdssid=Sunrisechannel=6ieee80211n=1hw_mode=gignore_broadcast_ssid=0wpa=2wpa_key_mgmt=WPA-PSKrsn_pairwise=CCMPwpa_passphrase=12345678