schematics Escher 3rd page
https://algo.mur.at/projects/microcontroller/escher/fotos/escherboard/schema3_3.png/view
https://algo.mur.at/projects/microcontroller/escher/fotos/escherboard/schema3_3.png/@@download/image/schema3_3.png
schematics Escher 3rd page