从理论上来说,任何一个WiFi设备都可以称位STA。STA是支持IEEE802.11协议的设备。 在大多数情况下,当大家说到STA模式时,一般是指具有WiFi client行为的设备,可以连接到接入点。 STA会扫描可连接的接入点,选择一个想要连接的接入点,经过认证、关联等步骤后,将与接入点进行连接。
WiFi扫描有两种不同的方式,一种是主动扫描,另一种是被动扫描。
static void WiFiInit(void)
{
printf("<--Wifi Init-->\r\n");
g_wifiEventHandler.OnWifiScanStateChanged = OnWifiScanStateChangedHandler;
g_wifiEventHandler.OnWifiConnectionChanged = OnWifiConnectionChangedHandler;
g_wifiEventHandler.OnHotspotStaJoin = OnHotspotStaJoinHandler;
g_wifiEventHandler.OnHotspotStaLeave = OnHotspotStaLeaveHandler;
g_wifiEventHandler.OnHotspotStateChanged = OnHotspotStateChangedHandler;
error = RegisterWifiEvent(&g_wifiEventHandler);
if (error != WIFI_SUCCESS)
{
printf("register wifi event fail!\r\n");
}
else
{
printf("register wifi event succeed!\r\n");
}
}
if (EnableWifi() != WIFI_SUCCESS)
{
printf("EnableWifi failed, error = %d\n", error);
return -1;
}
if (IsWifiActive() == 0)
{
printf("Wifi station is not actived.\n");
return -1;
}
info = malloc(sizeof(WifiScanInfo) * WIFI_SCAN_HOTSPOT_LIMIT);
if (info == NULL)
{
return -1;
}
do{
//重置标志位
ssid_count = 0;
g_staScanSuccess = 0;
//开始扫描
Scan();
//等待扫描结果
WaitSacnResult();
//获取扫描列表
error = GetScanInfoList(info, &size);
}while(g_staScanSuccess != 1);
printf("********************\r\n");
for(uint8_t i = 0; i < ssid_count; i++)
{
printf("no:%03d, ssid:%-30s, rssi:%5d\r\n", i+1, info[i].ssid, info[i].rssi/100);
}
printf("********************\r\n");
for(uint8_t i = 0; i < ssid_count; i++)
{
if (strcmp(SELECT_WIFI_SSID, info[i].ssid) == 0)
{
int result;
printf("Select:%3d wireless, Waiting...\r\n", i+1);
//拷贝要连接的热点信息
strcpy(select_ap_config.ssid, info[i].ssid);
strcpy(select_ap_config.preSharedKey, SELECT_WIFI_PASSWORD);
select_ap_config.securityType = SELECT_WIFI_SECURITYTYPE;
if (AddDeviceConfig(&select_ap_config, &result) == WIFI_SUCCESS)
{
if (ConnectTo(result) == WIFI_SUCCESS && WaitConnectResult() == 1)
{
printf("WiFi connect succeed!\r\n");
g_lwip_netif = netifapi_netif_find(SELECT_WLAN_PORT);
break;
}
}
}
if(i == ssid_count-1)
{
printf("ERROR: No wifi as expected\r\n");
while(1) osDelay(100);
}
}
if (g_lwip_netif)
{
dhcp_start(g_lwip_netif);
printf("begain to dhcp");
}
for(;;)
{
if(dhcp_is_bound(g_lwip_netif) == ERR_OK)
{
printf("<-- DHCP state:OK -->\r\n");
//打印获取到的IP信息
netifapi_netif_common(g_lwip_netif, dhcp_clients_info_show, NULL);
break;
}
printf("<-- DHCP state:Inprogress -->\r\n");
osDelay(100);
}
for(;; )
{
osDelay(100);
}