CPU: ATMega88 or ATMega48 Pin Name Usage ------------------------------------------------------ 1 PC6 (PCINT14/RESET) Pattern Write, track 0 2 PD0 (PCINT16/RXD) Pattern Write, track 1 3 PD1 (PCINT17/TXD) MIDI TXD 4 PD2 (PCINT18/INT0) Pattern Scan, Multiplex bit 0 5 PD3 (PCINT19/OC2B/INT1) Pattern Scan, Multiplex bit 1 6 PD4 (PCINT20/XCK/T0) Pattern Scan, Multiplex bit 2 7 VCC 8 GND 9 PB6 (PCINT6/XTAL1/TOSC1) XTAL1 10 PB7 (PCINT7/XTAL2/TOSC2) XTAL2 11 PD5 (PCINT21/OC0B/T1) Pattern Scan, Multiplex bit 3 12 PD6 (PCINT22/OC0A/AIN0) Tempo Up 13 PD7 (PCINT23/AIN1) Tempo Down 14 PB0 (PCINT0/CLK0/ICP1) Pattern Write, track 2 15 PB1 (OC1A/PCINT1) Pattern Write, track 3 16 PB2 (SS/OC1B/PCINT2) Sequence Display, Multiplex bit 3 17 PB3 (MOSI/OC2A/PCINT3) Sequence Display, Multiplex bit 0 18 PB4 (MISO/PCINT4) Sequence Display, Multiplex bit 1 19 PB5 (SCK/PCINT5) Sequence Display, Multiplex bit 2 20 AVCC 21 AREF 22 GND 23 PC0 (ADC0/PCINT8) Pattern Read, track 0 24 PC1 (ADC1/PCINT9) Pattern Read, track 1 25 PC2 (ADC2/PCINT10) Pattern Read, track 2 26 PC3 (ADC3/PCINT11) Pattern Read, track 3 27 PC4 (ADC4/SDA/PCINT12) Pattern Read, track 4 28 PC5 (ADC5/SCL/PCINT13) Pattern Write, track 4