rework of simple analog arpeggio to run on nano and with an external can 16bits ADS1115
typicaly the purpose was to add an arpeggiator to my korg MS10.
it ended with an arpeggiator mode and a looper mode arpeggiator accept 16 notes, looper samples and play up to 8 measures, all is clk or tap tempo synchronized, I hope
-vcoOut: pin9 (PWM16bits) -pwmLed: pin10 -gateIn: pin8 -gateOut: pin11 par defaut(modifiable)
-buttons&switch pin 3-7 --sw: START/STOP; HOLD; LOOP/ARP mode ; --push but: RESTART(connect on START sw) UNDO,BLANK,REPEAT
-TAP tempo push butt: pin 2 because we need int0 USED BY arp class
-duration rotary: adc6 pinA6 ; in loop mode : measures to sample and loop 1->8 -mode rotary: adc7 pinA7
