File content as of revision 0:35d70ff5c12e:

#include "mbed.h"
#include "BtnEventM0.h"

//        LSB                                                      MSB
BusOut lb(P1_13,P1_12,P1_7,P1_6,P1_4,P1_3,P1_1,P1_0,LED4,LED3,LED2,LED1);

BtnEventM0 sw4(P1_16), sw2(P0_15), sw1(P0_10), sw3(P0_23);

Timer t1;
void OneLeftStep();
void OneRightStep();
void ExecuteAutoButtons();

int main(void)
{
    lb = 1;
    sw4.Init();
    sw2.Init();
    sw1.Init();
    sw3.Init();
    t1.start();

    while(1) {
        if( sw4.CheckFlag() )
            OneRightStep();
        if( sw3.CheckFlag() )
            OneLeftStep();
        if( sw1.CheckFlag() )
            OneRightStep();
        if( sw2.CheckFlag() )
            OneLeftStep();
        ExecuteAutoButtons();
    }
}

void ExecuteAutoButtons()
{
    /* sw1.CheckButton();
    sw2.CheckButton();
    sw3.CheckButton();
    sw4.CheckButton(); */
}

void OneLeftStep()
{
    if( lb==2048 ) {
        lb = 1;
        return;
    }
    lb = lb << 1;
}

void OneRightStep()
{
    if( lb==1 ) {
        lb = 2048;
        return;
    }
    lb = lb >> 1;
}