unsigned char Get_Free_Layer(void) {
unsigned char ii,  jj=ALL_LEVELS_BUSY;
__disable_interrupt();
for(ii=0;ii<BUFER_LENGTH;ii++) {
if(Marker[ii] == FREE) {
Marker[ii] = OCCUPIED;
jj = ii;
break;
}
}
__enable_interrupt();
return jj;
}