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Wi-FI RTIP_RedPine_test example question


#1

I am trying to get the Wi-Fi WiFi RS21 Module working on my Cobra board.
I get exceptions when i run it.

In the example before the try catch of the WiFi.Enable there is this line:


NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);

when stepping through the code, it jumps to this method before the try catch WiFi.Enable can finish.
so if there is an error in try it will not jump to the catch of WiFi.Enable, it just stops.

So my question is, shouldn’t that NetworkChange, be moved elsewhere after the success of the try ?


#2

This is an event handler. What I think you’re experiencing is that the event is getting fired from within the try and the debugger is jumping out to the handler. The code is actually still within the try block. However, if this event fires often you may have a hard time stepping back into the try block. Try putting a stop within the try and then hit F5 to see if you can get back in.


#3

What happens is before it completes the try for WiFi.Enable. it fires the even handler. see below.
i dont think they should set up the event hadler before its confirmed that WiFi.Enable is ok.


        static void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
        {
            if (e.IsAvailable)
            {
                if (WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was established!");
                }
            }
            else
            {
                if (!WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was dropped or disconnected!");
                    network_is_read = false;
                }
            }
        }


#4

We will have an example ot get the new wifi up shortly.


#5

It sounds to me that the order of things is correct but the firing of the event is not. You would want to attach the event handler before the Enable because enabling WiFi essentially changes the state of network availability (assuming it works). It sounds to me that the problem is that the event is falsely being fired in anticipation of the network availability changing and not on it actually changing. I wouldn’t expect the event to fire until after Enable completed successfully. But, if you didn’t attach the handler until after Enable was called then you would miss the event of the network first becoming active. Of course, that could work if you made the assumption that you were starting in a state where the network was already available but that seems like the wrong way to do it to me.


#6

yes, this is the case, because even if you unplug the board the event fires.


#7

Here are the settings on FEZ Cobra if you are using WiFI RS21 with FEZ Cobra UEXT

WiFi.Enable(WiFi.HardwareModule.RS9110_N_11_21_1_Compatible, SPI.SPI_module.SPI2, (Cpu.Pin)2, (Cpu.Pin)26, (Cpu.Pin)3);// FEZ Cobra

and

WiFi.UpdateFirmware(WiFi.HardwareModule.RS9110_N_11_21_1_Compatible, SPI.SPI_module.SPI2, (Cpu.Pin)2, (Cpu.Pin)26, (Cpu.Pin)3);// FEZ Cobra

#8

FYI, I found the problem.

I commented out the event, then ran it. It then updated the wifi modules firmware.
i then uncommitted the event and now its running ok.

I think there should be a check of sorts to check the firmware version of the module before the event is attached.


#9

This event handler reflect the connection status of the current network interface. so it reflect Ethernt connection status by default.


#10

ok. but when the module needs a firmware update, this event was keeping it from getting it.
In the example anyway. Not saying that one could not write code to get around that. it was more of a FYI about the example.


#11

So the example code has to be modified. it should check wifi.isEnabled. Or as you mentioned, the event handler should be subscribed to after you make sure it is enabled.


#12

yes, i was just letting you know that the example should be tweaked like you suggested because if others try that example verbatim and their module needs a firmware update, it will not allow it to happen.


#13

hmm, I see that the even might fire before the the wifi is enabled because it is simply for Ethernet.
But I don’t see why would this fired event block the device from updating the firmware!

Do you mean that

WiFi.IsLinkConnected 

is raising the exception? in

static void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
        {
            if (e.IsAvailable)
            {
                if (WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was established!");
                }
            }
            else
            {
                if (!WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was dropped or disconnected!");
                    network_is_read = false;
                }
            }
        }

In this case, you are absolutely right. the example has to be modified to


 static void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
        {
if(WiFi.isEnabled)
{
            if (e.IsAvailable)
            {
                if (WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was established!");
                }
            }
            else
            {
                if (!WiFi.IsLinkConnected)
                {
                    Debug.Print("WiFi connection was dropped or disconnected!");
                    network_is_read = false;
                }
            }
}
        }

#14

the second snippet should work. I would try it but i have no idea how to roll the firmware back.

If you roll back your firmware on your module and try the example the way it sits you will see what i mean.

when the code first starts it subscribes the event first. then it tries to enable the wi-fi. Before it can complete this process the “NetworkChange_NetworkAvailabilityChanged” even fires and stops the whole thing. so it never gets to the catch where it will then allow it to update the firmware.


try
    {
        //WiFi.Enable(WiFi.HardwareModule.RS9110_N_11_21_1_Compatible, SPI.SPI_module.SPI2, (Cpu.Pin)10, (Cpu.Pin)18, (Cpu.Pin)20);// FEZ Spider Socket 6
        WiFi.Enable(WiFi.HardwareModule.RS9110_N_11_21_1_Compatible, SPI.SPI_module.SPI1, (Cpu.Pin)2, (Cpu.Pin)26, (Cpu.Pin)3);//EMX DevSys
        //WiFi.Enable(WiFi.HardwareModule.RS9110_N_11_21_1_Compatible, SPI.SPI_module.SPI2, (Cpu.Pin)64 + 9, (Cpu.Pin)19, (Cpu.Pin)64 + 8);//ChipworkX DevSys
    }
    catch (WiFi.HardwareException e)


#15

I could see what you mean. if WiFi.IsLinkConnected was called before enabling the wifi it the system get stuck.

The fixes is to check WiFi.isEnabled before calling WiFi.IsLinkConnected.