SCSPTR_SPB1DT
SHREG_SCSPTR = SCSPTR_SPB1IO | SCSPTR_SPB1DT
bit = (SHREG_SCSPTR & SCSPTR_SPB1DT) ? 1 : 0;
r |= SCSPTR_SPB1DT;
r &= ~SCSPTR_SPB1DT;
SHREG_SCSPTR |= SCSPTR_SPB1DT;
SHREG_SCSPTR &= ~SCSPTR_SPB1DT;
d = (SHREG_SCSPTR & SCSPTR_SPB1DT) ? 1 : 0;
SHREG_SCSPTR = SCSPTR_SPB1IO | SCSPTR_SPB1DT