143CHAPTER 6 PORT FUNCTIONSFigure 6-16. P71 and P72 Block DiagramPUO : Pull-up resistor option registerPM : Port mode registerRD : Port 7 read signalWR : Port 7 write signalP-chWRPMWRPORTRDWR PUOAVDDSelectorPUO7Output Latch(P71 and P72)PM71, PM72Internal busAlternate FunctionP71/SO2/TxD,P72/SCK2/ASCK