VIA1B_vRTCData
via1[vDirB] &= ~VIA1B_vRTCData;
data = (data << 1) | (via1[vBufB] & VIA1B_vRTCData);
via1[vDirB] |= VIA1B_vRTCData;
reg = via1[vBufB] & ~(VIA1B_vRTCClk | VIA1B_vRTCData);
via1[vDirB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData;