146CHAPTER 6 PORT FUNCTIONS6.2.9 Port 7This is a 3-bit input/output port with output latches. Input mode/output mode can be specified bit-wise by meansof port mode register 7 (PM7). When pins P70 to P72 are used as input port pins, an on-chip pull-up resistor canbe used as a 3-bit unit by means of pull-up resistor option register L (PUOL).Alternate functions include serial interface channel 2 data input/output and clock input/output.RESET input sets the input mode.Figures 6-15 and 6-16 show block diagrams of port 7.Caution When used as a serial interface, set the input/output and output latch according to its functions.For the setting method, refer to Table 19-2 Serial Interface Channel 2 Operating Mode Setting.Figure 6-15. P70 Block DiagramPUO : Pull-up resistor option registerPM : Port mode registerRD : Port 7 read signalWR : Port 7 write signalP-chWR PMWR PORTRDWR PUOV DDSelectorPUO7Output Latch(P70)PM70Internal busP70/SI2/RxD
