When starting the game, you can also select between both players, the one, who should serve first.
If both racquets stand at the top, the computer plays both sides. The game speed will be chosen ran-
domly.
Technical description
The core of the game is an ATmega8 controller. A matrix with 120 LEDs is arranged in ten series of
12 LEDs each. The microcontroller controls the series using a multiplex process. In this process, the
anodes are directly driven via ports, whereas the cathodes are driven via two shift registers HC4094.
The potentiometers are queried over ADC6 and ADC7. The upper end of the potentiometers is located
on VCC and the lower end on port PD2 (INT0). After the end of a game, the program shifts PD2 up, so
that there is no voltage in the potentiometers. All LEDs are switched off, the AD converter is stopped
and the microcontroller is shifted into the power down mode. The power consumption then drops to
below 1 µA. Therefore no main switch is required. The coin contact (K1 and K2) is also located on PD2
and GND. This can thus cause an interruption and restart the game.
28
Speed level 3
