潘多拉 RT-Thread WiFi 管理
实验概述
本实验使用 RT-Thread Wlan Manager 对 WiFi 网络管理，展示 WiFi 热点扫描、Join 网络、WiFi 自动连接以及 WiFi Event 处理等功能。
硬件连接
潘多拉 IoT Board 板载的一个 WiFi 模块，它是正基公司的 AP6181 WiFi 模组，集成了 IEEE 802.11 b/g/n MAC 、基带、射频以及功率放大器、电源管理装置、SDIO 2.0 接口，原理图如下。
示例代码
程序主要流程：首先调用 Scan 接口扫描周围环境中的 AP（Access Point ，即无线访问热点），并打印扫描结果；然后连接一个测试用的 AP（名字 test_ssid，密码 12345678），并等待联网成功，打印网络信息；接着在等待 5 秒之后，断开和 AP 的连接；最后，调用接口初始化自动连接的相关配置，开启自动连接功能。在开启自动连接之后，Wlan Manager 会根据存储介质中的历史记录进行 AP 连接。
参考《潘多拉 IoT Board 开发环境》创建工程，在 applications/main.c 中输入如下代码。
注意：将 WLAN_SSID 和 WLAN_PASSWORD 修改为你的 WiFi 接入点名称和密码。
applications/main.c
#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>
#include <msh.h>
#include "drv_wlan.h"
#include "wifi_config.h"
#include <stdio.h>
#include <stdlib.h>
#define DBG_TAG "main"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>
#define WLAN_SSID "test_ssid"
#define WLAN_PASSWORD "12345678"
#define NET_READY_TIME_OUT (rt_tick_from_millisecond(15 * 1000))
static void print_scan_result(struct rt_wlan_scan_result *scan_result);
static void print_wlan_information(struct rt_wlan_info *info);
static struct rt_semaphore net_ready;
void wlan_ready_handler(int event, struct rt_wlan_buff *buff, void *parameter)
{
rt_sem_release(&net_ready);
}
/* 断开连接回调函数 */
void wlan_station_disconnect_handler(int event, struct rt_wlan_buff *buff, void *parameter)
{
LOG_I("disconnect from the network!");
}
int main(void)
{
int result = RT_EOK;
struct rt_wlan_info info;
struct rt_wlan_scan_result *scan_result;
/* 等待 500 ms 以便 wifi 完成初始化 */
rt_hw_wlan_wait_init_done(500);
/* 扫描热点 */
LOG_D("start to scan ap ...");
/* 执行同步扫描 */
scan_result = rt_wlan_scan_sync();
if (scan_result)
{
LOG_D("the scan is complete, results is as follows: ");
/* 打印扫描结果 */
print_scan_result(scan_result);
/* 清除扫描结果 */
rt_wlan_scan_result_clean();
}
else
{
LOG_E("not found ap information ");
return -1;
}
/* 热点连接 */
LOG_D("start to connect ap ...");
rt_sem_init(&net_ready, "net_ready", 0, RT_IPC_FLAG_FIFO);
/* 注册 wlan ready 回调函数 */
rt_wlan_register_event_handler(RT_WLAN_EVT_READY, wlan_ready_handler, RT_NULL);
/* 注册 wlan 断开回调函数 */
rt_wlan_register_event_handler(RT_WLAN_EVT_STA_DISCONNECTED, wlan_station_disconnect_handler, RT_NULL);
result = rt_wlan_connect(WLAN_SSID, WLAN_PASSWORD);
if (result == RT_EOK)
{
rt_memset(&info, 0, sizeof(struct rt_wlan_info));
/* 获取当前连接热点信息 */
rt_wlan_get_info(&info);
LOG_D("station information:");
print_wlan_information(&info);
/* 等待成功获取 IP */
result = rt_sem_take(&net_ready, NET_READY_TIME_OUT);
if (result == RT_EOK)
{
LOG_D("networking ready!");
msh_exec("ifconfig", rt_strlen("ifconfig"));
}
else
{
LOG_D("wait ip got timeout!");
}
/* 回收资源 */
rt_wlan_unregister_event_handler(RT_WLAN_EVT_READY);
rt_sem_detach(&net_ready);
}
else
{
LOG_E("The AP(%s) is connect failed!", WLAN_SSID);
}
rt_thread_mdelay(5000);
LOG_D("ready to disconect from ap ...");
rt_wlan_disconnect();
/* 自动连接 */
LOG_D("start to autoconnect ...");
/* 初始化自动连接配置 */
wlan_autoconnect_init();
/* 使能 wlan 自动连接 */
rt_wlan_config_autoreconnect(RT_TRUE);
return 0;
}
static void print_scan_result(struct rt_wlan_scan_result *scan_result)
{
char *security;
int index, num;
num = scan_result->num;
/* 有规则的排列扫描到的热点 */
rt_kprintf(" SSID MAC security rssi chn Mbps\n");
rt_kprintf("------------------------------- ----------------- -------------- ---- --- ----\n");
for (index = 0; index < num; index++)
{
rt_kprintf("%-32.32s", &scan_result->info[index].ssid.val[0]);
rt_kprintf("%02x:%02x:%02x:%02x:%02x:%02x ",
scan_result->info[index].bssid[0],
scan_result->info[index].bssid[1],
scan_result->info[index].bssid[2],
scan_result->info[index].bssid[3],
scan_result->info[index].bssid[4],
scan_result->info[index].bssid[5]);
switch (scan_result->info[index].security)
{
case SECURITY_OPEN:
security = "OPEN";
break;
case SECURITY_WEP_PSK:
security = "WEP_PSK";
break;
case SECURITY_WEP_SHARED:
security = "WEP_SHARED";
break;
case SECURITY_WPA_TKIP_PSK:
security = "WPA_TKIP_PSK";
break;
case SECURITY_WPA_AES_PSK:
security = "WPA_AES_PSK";
break;
case SECURITY_WPA2_AES_PSK:
security = "WPA2_AES_PSK";
break;
case SECURITY_WPA2_TKIP_PSK:
security = "WPA2_TKIP_PSK";
break;
case SECURITY_WPA2_MIXED_PSK:
security = "WPA2_MIXED_PSK";
break;
case SECURITY_WPS_OPEN:
security = "WPS_OPEN";
break;
case SECURITY_WPS_SECURE:
security = "WPS_SECURE";
break;
default:
security = "UNKNOWN";
break;
}
rt_kprintf("%-14.14s ", security);
rt_kprintf("%-4d ", scan_result->info[index].rssi);
rt_kprintf("%3d ", scan_result->info[index].channel);
rt_kprintf("%4d\n", scan_result->info[index].datarate / 1000000);
}
rt_kprintf("\n");
}
static void print_wlan_information(struct rt_wlan_info *info)
{
LOG_D("SSID : %-.32s", &info->ssid.val[0]);
LOG_D("MAC Addr: %02x:%02x:%02x:%02x:%02x:%02x", info->bssid[0],
info->bssid[1],
info->bssid[2],
info->bssid[3],
info->bssid[4],
info->bssid[5]);
LOG_D("Channel: %d", info->channel);
LOG_D("DataRate: %dMbps", info->datarate / 1000000);
LOG_D("RSSI: %d", info->rssi);
}
完整代码：16_iot_wifi_manager
编译运行
开启 WiFi 选项
下载软件包
$ pkgs --update
==============================> WLAN_WICED v1.0.1 is downloaded successfully.
==============================> EASYFLASH v4.1.0 is downloaded successfully.
==============================> FAL v0.5.0 is downloaded successfully.
==============================> STM32_SDIO v1.0.2 is downloaded successfully.
Operation completed successfully.
编译工程
$ scons
...
LINK rtthread-stm32l4xx.elf
arm-none-eabi-objcopy -O binary rtthread-stm32l4xx.elf rt-thread.bin
arm-none-eabi-size rtthread-stm32l4xx.elf
text data bss dec hex filename
345732 2460 43584 391776 5fa60 rtthread-stm32l4xx.elf
scons: done building targets.
将 bin 文件上传到 STM32
st-flash write rt-thread.bin 0x8000000
打开串口终端，输出如下内容
\ | /
- RT - Thread Operating System
/ | \ 4.0.1 build Jan 4 2022
2006 - 2019 Copyright by rt-thread team
lwIP-2.0.2 initialized!
[I/sal.skt] Socket Abstraction Layer initialize success.
[SFUD] Find a Winbond flash chip. Size is 16777216 bytes.
[SFUD] w25q128 flash device is initialize success.
msh />[I/FAL] RT-Thread Flash Abstraction Layer (V0.2.0) initialize success.
[I/OTA] RT-Thread OTA package(V0.1.3) initialize success.
[I/OTA] Verify 'wifi_image' partition(fw ver: 1.0, timestamp: 1529386280) success.
[I/WLAN.dev] wlan init success
[I/WLAN.lwip] eth device init ok name:w0
打印扫描结果
[D/main] start to scan ap ...
[E/SDIO] err:0x00400404, CTIMEOUT cmd:53 arg:0x94404004 rw:w len:4 blksize:4
[D/main] the scan is complete, results is as follows:
SSID MAC security rssi chn Mbps
------------------------------- ----------------- -------------- ---- --- ----
FCTC_89 78:11:dc:38:f0:c0 WPA2_MIXED_PSK -30 1 144
EZVIZ_D91768381 60:23:a4:d5:c5:a8 WPA2_AES_PSK -70 6 65
EZVIZ_D96630777 60:23:a4:d6:2c:0b WPA2_AES_PSK -82 6 65
CMCC-dy73 b8:e3:b1:0d:b4:50 WPA2_MIXED_PSK -87 8 144
Tineco_3296 8e:ce:4e:ea:d0:bc OPEN -88 1 54
CMCC-123 34:55:94:9b:a4:de WPA2_AES_PSK -88 3 300
Rudy-Lab 5c:02:14:d3:ef:97 WPA2_MIXED_PSK -88 10 144
连接 WiFi 网络
[D/main] start to connect ap ...
[I/WLAN.mgnt] wifi connect success ssid:FCTC_89
[D/main] station information:
[D/main] SSID : FCTC_89
[D/main] MAC Addr: 78:11:dc:38:f0:c0
[D/main] Channel: 1
[D/main] DataRate: 144Mbps
[D/main] RSSI: -30
[D/main] networking ready!
network interface device: w0 (Default)
MTU: 1500
MAC: 18 93 7f 7f 61 94
FLAGS: UP LINK_UP INTERNET_DOWN DHCP_ENABLE ETHARP BROADCAST IGMP
ip address: 192.168.3.183
gw address: 192.168.3.1
net mask : 255.255.255.0
dns server #0: 192.168.3.1
dns server #1: 0.0.0.0
[I/WLAN.lwip] Got IP address : 192.168.3.183
断开 WiFi 连接
warning: tcpip stack is close to end of stack address.
warning: tcpip stack is close to end of stack address.
[D/main] ready to disconect from ap ...
[I/main] disconnect from the network!
[I/WLAN.mgnt] disconnect success!
自动重连
[D/main] start to autoconnect ...
[Flash] EasyFlash V3.2.1 is initialize success.
[Flash] You can get the latest version on https://github.com/armink/EasyFlash .
[I/WLAN.mgnt] wifi connect success ssid:FCTC_89
[I/WLAN.lwip] Got IP address : 192.168.3.183
查看网卡状态
msh />ifconfig
network interface device: w0 (Default)
MTU: 1500
MAC: 18 93 7f 7f 61 94
FLAGS: UP LINK_UP INTERNET_UP DHCP_ENABLE ETHARP BROADCAST IGMP
ip address: 192.168.3.183
gw address: 192.168.3.1
net mask : 255.255.255.0
dns server #0: 192.168.3.1
dns server #1: 0.0.0.0
测试网络连通性
msh />ping getiot.tech
60 bytes from 42.192.64.149 icmp_seq=0 ttl=51 time=46 ms
60 bytes from 42.192.64.149 icmp_seq=1 ttl=51 time=45 ms
60 bytes from 42.192.64.149 icmp_seq=2 ttl=51 time=44 ms
60 bytes from 42.192.64.149 icmp_seq=3 ttl=51 time=44 ms
MSH 命令
为了方便用户验证 WiFi 功能是否正常，配置 WiFi 网络，RT-Thread 提供了 wifi 相关的 shell 命令。
wifi # 打印帮助
wifi help # 查看帮助
wifi join SSID [PASSWORD] # 连接 wifi，SSDI 为空，使用配置自动连接
wifi ap SSID [PASSWORD] # 建立热点
wifi scan # 扫描全部热点
wifi disc # 断开连接
wifi ap_stop # 停止热点
wifi status # 打印 wifi 状态 sta + ap
wifi smartconfig # 启动配网功能
思考总结
通过本实验，我们学习了 WiFi 网络扫描、联网、开启自动连接等功能。WiFi 功能的实现有赖 WiFi 模组库和驱动的支持。其中，AP6181 WiFi 模组使用 Cypress 公司的 WICED 软件包，这部分代码已经在 RT-Thread 上完成移植和适配，以库文件的形式提供。用户仅需调用 RT-Thread Wlan Manager 层 API 即可轻松操作。
WiFi 驱动位于 drivers/drv_wlan.c 中，主要完成 WiFi 库的初始化，以及 WiFi 固件的读取。本例中 WiFi 固件存储于外部 NorFlash 的 wifi_imager 分区，程序启动时从 Flash 读取固件，然后通过 SDIO 传输至 AP6181 WiFi 模组。
drv_wlan.c 中实现了两个重要的接口，完成 WiFi 固件的读取，并在 WiFi 库中被调用。
int wiced_platform_resource_size(int resource);
获取 WiFi 固件的大小。该接口用于从偏移位置读取指定大小的固件到 buffer 中，返回值为实际读取的固件大小。
int wiced_platform_resource_read(int resource,
uint32_t offset,
void *buffer,
uint32_t buffer_size);
本实验中用到的 AP6181 WiFi 模组，需要配合专用 WiFi 固件使用。开发板在出厂前已经烧录过 WiFi 固件，默认存储在外部 Flash。如果固件被不慎擦除，请参考 UM3001《IoT-Board WiFi 固件下载》，进行重新烧录。