schematics Escher 2nd page
https://algo.mur.at/projects/microcontroller/escher/fotos/escherboard/schema2_3.png/view
https://algo.mur.at/projects/microcontroller/escher/fotos/escherboard/schema2_3.png/@@download/image/schema2_3.png
schematics Escher 2nd page