Integral Design

Initializing the GHI Electronics WiFi RS21 module involves some different issues than initializing the Ethernet_J11D Module.  It took several runs to get my WiFi module working.  I don’t know all the permutations of WiFi networking, so I used a trial-and-error approach.

WiFi_RS21 Module and Fez Spider Mainboard

First, I plugged in the WiFi_RS21 module and added start-up code, equivalent to what I have been using with my ethernet module, to the ProgramStarted method .  When I started the deployment, the debugger output reported that the WiFi module was being reflashed; evidently the new SDK or driver includes an update.  It worked smoothly and re-flashed the module in about 30 seconds.  But, my initialization code was inadequate or in the wrong sequence, or both, so the application threw an exception.

The start-up process was hanging before it reached the end of the ProgramStarted method, that is, the debugger output didn’t show “Program Started” before the application threw an exception.  I thought the code was wrong, so I tinkered with it a bit, but I kept getting errors.  Because my code was wrong, and, because it was in the ProgramStarted method, it kept the application from running.  A few more attempts in this vein led to a situation where the mainboard lost communication with Visual Studio, and deployment to the mainboard was corrupted.  Resetting the device in the Project Properties/ .NET Micro Framework/Transport/USB/ to EMX_Gadgeteer was useful, but I had to run another application that I knew worked to get past this dilemma.

The requirements, in my environment, include the following settings of the WiFi_RS21 and the WiFiNetworkInfo object.

    wifi.UseDHCP();
    Gadgeteer.Modules.GHIElectronics.WiFi_RS21.WiFiNetworkInfo info = new WiFi_RS21.WiFiNetworkInfo();
    info.SSID = "MySecurityID";
    info.SecMode = WiFi_RS21.SecurityMode.WEP;
    info.networkType = WiFi_RS21.NetworkType.AccessPoint;
    wifi.Join(info, "PassPhrase");

To initialize the WiFiNetworkInfo object, you’ll need the SSID that your router provides for WiFi connections, and you have to identify the Security Mode (SecMode).  The SecMode options are listed in an enumeration that is part of the .NET Gadgeteer Core SDK as follows: Open: Not secured; WEP: Wired Equivalency Privacy; WPA: Wi-Fi Protected Access; WPA2: Wi-Fi Protected Access II.  There is another enumeration for NetworkType: AccessPoint or AdHoc (I don’t know the difference, but there are only two options).  These few properties of the WiFiNetworkInfo object were enough to get my module to run by calling the WiFi_RS21.Join method.  Now that the module is working, I’ve found that I can run all the initialization code in ProgramStarted.

In order to know when and if the WiFi connection is working, you’ll also want to initialize delegates for the NetworkUp and NetworkDown event handlers.

 wifi.NetworkUp += new GTM.Module.NetworkModule.NetworkEventHandler(ethernet_NetworkUp);
 wifi.NetworkDown += new GTM.Module.NetworkModule.NetworkEventHandler(ethernet_NetworkDown);

For testing, all you’ll need is the NetworkUp delegate that prints information to the debugger as shown in the following code.  The NetworkUp delegate also illustrates a quick way to get the IP address for extending this application to make use of this new WiFi connection.

    Private void ethernet_NetworkUp(GTM.Module.NetworkModule sender, GTM.Module.NetworkModule.NetworkState state)
    {
        Debug.Print("Network Up!");
        Debug.Print("IP Address: " + wifi.NetworkSettings.IPAddress);
    }
    private void ethernet_NetworkDown(GTM.Module.NetworkModule sender, GTM.Module.NetworkModule.NetworkState state)
    {
        Debug.Print("Network Down!");
    }