G.G. (Italy)
555 as a tone generator for the Z80
The seven trimmers (all connected to a 555 oscillating circuit) are tuned to play the seven musical notes (Major Scale). The two quad analog/bilateral switch 4016 select the appropriate resistor, according to a seven bits word. The last bit is used to activate or mute the sound. The amplifier is just a simple general purpose low-power amplifying transistor (2N2222A).
555 as a tone generator for the Z80
The seven trimmers (all connected to a 555 oscillating circuit) are tuned to play the seven musical notes (Major Scale). The two quad analog/bilateral switch 4016 select the appropriate resistor, according to a seven bits word. The last bit is used to activate or mute the sound. The amplifier is just a simple general purpose low-power amplifying transistor (2N2222A).