I started designing a musical keyboard / synthesizer
| Parts | Purpose |
|---|---|
| Atmega328 or attiny84 | main uC |
| 512kb RAM Module | Sound-Buffer for Replay and loop effect |
| 19bit counter | visits every adress of the RAM module to read and write samples |
| 555 timer with potentiometer | to create a variadic clock signal |
| 8bit flip-flop register 1 | saves the adress of recording end so counter will reset when max-adress is reached |
| 8bit magnitude comparator | compares the counter to saved value and resets it, so the recording size is variable |
| 8bit flip-flop register 2 | buffers the output of the RAM, otherwise we pick up the clock frequency at the final audio signal |
| buttons and diodes | for user input |
| shift register | to charlieplex the button state row selection |
| Digital Adder | adds the digital audio samples from the external ram and the live samples from the main uC |
| Digital to Analog converter DAC |
converts the digital audio samples to an analog signal |
