This is an Ultibo application and device driver which enables support for the internal WIFI device (a Cypress 43445 based chip). It supports WPA2/PSK encryption and additionally allows connection to an open network (although this is not generally recommended for security reasons).
The device driver currently supports Pi ZeroW, PiZero2W, Pi3, Pi4, and Pi400. It also supports compute module devices with onboard WIFI although these have only been tested by others as I do not have any on my test bench.
USB WIFI devices are not supported.
This readme refers to two versions of the WIFI component used for negotiating encyption keys with a WPA2 secured router:
- Firmware supplicant: This is provided by Broadcom as part of the WIFI subsystem.
- Software supplicant: This is the more traditional supplicant that is present on most Linux platforms (and others e.g. windows).
- Pi Zero - both the firmware supplicant and the software supplicant are supported.
- Pi Zero2W - the software supplicant is required to connect to an encrypted network. If not using the software supplicant, only an open network can be used because the Broadcom WIFI firmware for this device does not include a firmware supplicant.
- Pi3b and 3b+ - both the firmware supplicant and the software supplicant are supported.
- Pi4 - both the firmware supplicant and the software supplicant are supported.
- Pi400 - the software supplicant is required to connect to an encrypted network. If not using the software supplicant, only an open network can be used because the Broadcom WIFI firmware for this device does not include a firmware supplicant.
The demo kernel will connect to the WIFI network you have configured and it contains telnet access, so you can use Ultibo's standard set of shell commands if you telnet to it (port 23). This includes the ability to upgrade the kernel if you set up a local web server and point your cmdline.txt to it in the usual way (see Ultibo website for details on how to do this). I have also enabled the webstatus unit so that you can connect a browser to the IP address and view system information over the wifi network. See Ultibo website for details on this also.
If you are using the firmware supplicant, I have added some support for selecting a specific network via a combination of the SSID (the usual router name) and the BSSID (a MAC address). This enables a specific network address to be targetted in situations where a router broadcasts the same SSID for two different frequency bands (e.g. 5Ghz and 2.4Ghz). The two bands will likely have separate BSSIDs to support that.
For the software supplicant, all configuration is done via c:\wpa_supplicant.conf. A blank conf file is included in the demo kernel download. The software supplicant version used is version 2.9, so you may refer to the Linux supplicant documentation for details on additional configuration options. I have not tested anything but the most basic configuration of router id and password.
Please note that this device driver has no support for enabling the device as an access point at this time (regardless of which supplicant is being used) and therefore any configuration that is valid for Linux in this regard definitely will not work
Kernel images are compiled with a blocking initial connect but will work fine if you change the relevant parameter to non-blocking in the connect call and recompile.
To get access to the demo binaries without needing to recompile anything, download the demo zip file asset from the release section. Note there is no release for the develop branch, so people requiring early access will need to build from source and use the blank wpa_supplicant.conf file found in the repo for configuration.
Note that the demo kernels are now all compiled with the software supplicant because this keeps the configuration consistent across all devices.
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Download the ZIP file from the releases area (links on the right of this page when displayed on github.com).
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Extract the contents of the zip file to an empty SD card. Be sure to maintain the directory structure i.e. retain the firmware folder and its contents.
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Edit the c:\wpa_supplicant.conf file, fill in the router name and password into the spaces provided, then boot the device. Your router name is likely to be case sensitive.
You must recompile the source to switch the software supplicant off and hence enable the firmware supplicant. To do this, ensure you build without the "supplicant" compiler directive. You will find this in the project settings.
To log on to a network with the firmware supplicant you need to specify your router settings in the cmdline.txt file that is part of the demo image. Add the name of your router, the password, and your ISO country code.
SSID=<ssid name> KEY=<passphrase> COUNTRY=<2 char ISO country code>
For an open network, KEY= can be left empty (or not included). Use of open networks is obviously not recommended but is necessary for Pi400 and PiZero2W when the firmware supplicant is being used.
If you want to see a scan for base stations, add
WIFISCAN=1
if you want to select a specific network interface, then in addition to the SSID you can specify the BSSID viz;
BSSID=xx:xx:xx:xx:xx:xx
Obviously, replace the xx's with your router interface's MAC address. This setting is not normally required. You must use the exact format given above although case of the characters doesn't matter.
Note that the SSID is most likely case sensitive so copy your router's ID exactly.
Don't forget that cmdline.txt must have all entries on the same line.
You must update to the latest ultibo core to successfully compile this software. At the time of writing this is Ultibo Core 2.1.079 but anything newer than this is fine.
The application will compile in Ultibo Lazarus if you open the wifi project and have met the necessary Core version requirements.
By default, supplicant support is not included unless you define the compiler directive 'supplicant'. In order to build with the supplicant the repo contains pre-built supplicant libraries for each of the target processors, hence you won't need to compile any of the C code to get started. There is a condtional define at the top of the wifidevice.pas file that deals with including the correct library version.
If for any reason you want to actually build the supplicant library from source, there are makefiles in the wpasupplicant subdirectory of the repo. Building the supplicant requires issuing one or more of the following commands, depending upon which device you are targeting:
make -f Makefile.Ultibo libwpa_supplicant_pizero.a
make -f Makefile.Ultibo libwpa_supplicant_pi3.a
make -f Makefile.Ultibo libwpa_supplicant_pi4.a
Use Pi4 for a Pi400 as well, and use pi3 for a PiZero2w. The resultant libraries are placed in the relevant device related subfolder ready for compiling into an application via the wifidevice unit. You won't need to copy them to any other location when compiling your Ultibo application.
See the contents of wifi.lpr for how this is currently done. It will change in the future as presently the devices are being created outside of the Ultibo initialization process in order to manage the dependency on the C: drive for firmware loading. This part is important - the C: drive must be registered before initiaising the device otherwise the firmware upload to the WIFI chip will fail.
wifi.lpr currently contains code to activate both the firmware and software based supplicants. If you are building your own application you won't need both capabilities so just pick the code out for the relevant version.
Note that firmware or software based supplicant is a compile time choice; there is no capability to switch between them at runtime.