After finishing the YOCTO2, I realized that the DATA-KNOB did not work.
I checked the DATA KNOB. He seemed to work.
I checked the connections from the DATA-KNOB to the ATmega1284P. Was OK.
I wrote a message to e-licktronic.com in the contact form.
Vincent replied, "Update the firmware with the 2.003beta fixed the issue."
When asked how to do that, he replied, "There is a process to upload the firmware available in the forum via SYSEX."
I wrote to him that I had not read anything about it, but that some used the programmer WINGONEER TTL866II.
His answer: The sysex firmware is available in the forum. Then you need a midi interface connected to your computer. Download a Sysex loader like midiox or C6. Then connect your midi out interface to the midi in of the yocto. Power up your yocto while holding 1,3,5 steps button, all leds wants to flash then send the sysex via the software. Wait until your yocto reboot. Your done.
I bought a midi interface, installed midi-ox, downloaded the sysex firmware and connected PC and yocto via the midi interface. But powering up my yocto while holding 1,3,5 steps button had no effect.
I wrote that to Vincent and have not got an answer since ...
Solving:
I bought the XGecu TTL866II plus universal programmer, saved the Atmega contents (2.003) on the PC and flashed 2.003beta.
When I turned on my yocto2 all LED lit up. The yocto2 responded to no input while terrible sounds came from the speakers.
I flashed the original 2.003. The same lights and noises.
Maybe the fuse bits are wrong. I needed information. I found two Fusebit calculators.
https://eleccelerator.com/fusecalc/fuse ... tmega1284p and
http://www.engbedded.com/fusecalc/
I played around a bit and flashed 2.003beta, leaving all fusebits unchecked.
The Yocto2 works, even the DATA KNOB. Yippee !!!
I played around a bit again and flashed 2.003, leaving all fusebits unchecked.
Guess what? The Yocto2 works as well. Yay!
There is obviously no problem with the software, but with the fusebits!