The LED control shows up as a serial device in Linux as well as Windows. When interacting with a serial device, commonly following properties need to be known:
- baud rate
- character size
- stop bits
- etc.
(notice: see, e.g. the serialport crate documentation [1] for further )
In this case, two approaches have been taken to retrieve the user options.
The reddit user fairedemmy [2] sniffed the data sent to the serial port. By changing around values and looking at the intercepted data, it can be determined how the LEDs are set.
fairedemmy [2] shared a link to LedControl.exe that is responsible for controlling the LEDs.
Once downloaded, the can be decompiled using tools, such as ILSpy [3] and dnSpy [4].
The decompilers are able to decompile the .NET bytecode into C#.
Looking over the code, the file Form2 is of great interest.
In this file, one can find the code that configures the connection to the serial port:
...
private void openPort()
{
this.sp.PortName = this.portName;
this.sp.BaudRate = 10000;
this.sp.DataBits = 8;
this.sp.StopBits = StopBits.One;
this.sp.Parity = Parity.None;
this.sp.ReadTimeout = 200;
try
{
this.sp.Open();
this.openState = true;
}
catch (IOException)
{
this.openState = false;
}
}
...Further down, e.g. the LED's mode is set to off:
...
private void pictureBox1_guandeng_Click(object sender, EventArgs e)
{
this.CurrentLedMode = 4;
this.arrSerialData[1] = (byte)this.CurrentLedMode;
this.Send_data(this.arrSerialData);
this.setPicboxImage();
}
...Looking over the code, the existing findings, which were obtained by intercepting the data sent to the serial port, were confirmed.
Sadly, no further modes were found, such as a solid colour mode.
[1] https://docs.rs/serialport/latest/serialport/trait.SerialPort.html
[2] https://old.reddit.com/user/fairedemmy
[3] https://github.com/icsharpcode/ILSpy
[4] https://github.com/dnSpyEx/dnSpy