// (D'Arcy's) shiftOut subroutine: 
    // Assumption(s): ATmega328P, DATA on PB0, CLOCK on PB3, Latch is LOW
    //              : LSBFIRST, data in r22
    // Register Use: r23 for count
    "shiftOut:              \n"    // Shiftout subroutine LSBfirst
    "push r23                \n"    // preserve incoming value in r23
    "ldi  r23,8             \n"    // set count to 8
    "nextBit:               \n"
    "cbi 0x05,3             \n"    // set clock LOW
    "cbi 0x05,0             \n"    // assume data LOW
    "sbrc r22,0             \n"    // skip next statement if our assumption was correct
    "sbi  0x05,0            \n"    // set data HIGH
    "sbi 0x05,3             \n"    // set clock HIGH
    "lsr  r22               \n"    // Shift the byte to the right one position
    "dec  r23               \n"    // reduce count
    "brne nextBit           \n"    //
    "pop  r23               \n"    // restore value in r23 for outgoing
    "ret                    \n"    //