Hmm there is a possibility that if you plug an ethernet-USB interface that does not require drivers on Linux, it will "automagically" work. If you have a USB ethernet adapter kicking around, it is worth chancing it: plug it in, reboot the board, and try to access it at bela.local
. If that fails, try to connect it to you home router, and see if it gets assigned an IP there.
If this doesn't work, then you'll need to somehow find a way to access the files on the board. There are a number of options. The easiest (and it's not so easy!) is explained below. Another option would be to have a Linux machine (e.g.: another Bela, or a laptop/desktop computer), or a Windows or Mac machine with the capability of reading/writing ext4 file systems. This would require a bit of guesswork, but could potentially work.
Recommended option:
You need some sort of serial adapter to log remotely into BelaMini. If you have another Bela around, you can just follow the instructions here, where "Bela1" would be the fully working Bela, and Bela2 would be your damaged BelaMini. If you don't have another Bela around, but you have some sort of UART/FTDI adapter to allow you to open a serial connection from your computer, then you can use that instead of Bela1. Most other single-board computers (e.g.: a RaspberryPi) probably have serial capabilities, check their documentation for details.
Regardless of how you are trying to connect to your BelaMini over serial, you will have to prepare the board by following the instructions in "Preparing Bela2".
You also need to power on the board: connect a 5V voltage source to P1.01 ("Vin"). Connect the ground from the power supply to any of the GND pins (check out the diagram here).
If that works successfully, then you can log into the board. Note that because of the changes you had to make while "Preparing Bela2", the audio will not work at the moment. This can be fixed, if you are interested in connecting over serial in the long run.
Now that you are in, let's think about the fix. Here are a few possible solutions
USB ethernet adapter
As long as the adapter is supported by Linux, this should be fairly straightforward.
Plug in the adapter, wait a couple of seconds, run lsusb
to check that it shows up as a device. Then run ip a
and make sure it shows up as a network interface, probably called eth0
. If it does, then edit /etc/network/interfaces
, comment out the current entry for eth0
, and duplicate the four lines for usb1
, replacing usb1
with eth0
.
USB WiFi adapter
That's another option. Find a WiFi dongle that is fully compatible with Linux 4.4, and follow the instructions here (there are also some suitable devices listed there).
Using the USB port on the header as a substitute for the port you snapped off
This should be doable, but I have never tried it. There are at least a couple software mods to be made:
- edit /opt/dtb-rebuilder/src/arm/am335x-pocketbeagle-common.dtsi
so that line 996 becomes dr_mode = "otg";
, then make -C /opt/dtb-rebuilder install
)
- edit /opt/Bela/bela_gadget.sh
and replace all usb0
with usb1
However, I am not sure what needs to be done from a hardware point of view. You definitely need a USB-A to USB-A cable, but you may have to disconnect (that is: cut) the USB VBUS pin (P1.5), and possibly connect the USB VIN pin (P1.7). However, I haven't tried any of these, so I'd recommend you look into further documentation before attempting hardware modifications, or even connecting a USB-A to USB-A cable.