SHREG_SCSPTR
SHREG_SCSPTR = SCSPTR_SPB1IO | SCSPTR_SPB1DT
uint8_t r = SHREG_SCSPTR;
SHREG_SCSPTR = r;
uint8_t r = SHREG_SCSPTR;
SHREG_SCSPTR = r;
bit = (SHREG_SCSPTR & SCSPTR_SPB1DT) ? 1 : 0;
uint8_t r = SHREG_SCSPTR;
SHREG_SCSPTR = r;
SHREG_SCSPTR |= SCSPTR_SPB1DT;
SHREG_SCSPTR &= ~SCSPTR_SPB1DT;
d = (SHREG_SCSPTR & SCSPTR_SPB1DT) ? 1 : 0;
SHREG_SCSPTR = SCSPTR_SPB1IO | SCSPTR_SPB1DT
SHREG_SCSPTR |= SCSPTR_SPB0DT;
SHREG_SCSPTR &= ~SCSPTR_SPB0DT;
SHREG_SCSPTR |= SCSPTR_SPB1IO;
SHREG_SCSPTR &= ~SCSPTR_SPB1IO;