80CHAPTER 4 PIN FUNCTION (μPD78054Y Subseries)4.2 Description of Pin Functions4.2.1 P00 to P07 (Port 0)These are 8-bit input/output ports. Besides serving as input/output ports, they function as an external interruptrequest input, an external count clock input to the timer, a capture trigger signal input, and crystal connection forsubsystem oscillation.The following operating modes can be specified in 1-bit units.(1) Port modeP00 and P07 function as input-only ports and P01 to P06 function as input/output ports.P01 to P06 can be specified for input or output ports in 1-bit units with a port mode register 0 (PM0). Whenthey are used as input ports, on-chip pull-up resistors can be used to them by defining the pull-up resistoroption register L (PUOL).(2) Control modeIn this mode, these ports function as an external interrupt request input, an external count clock input to thetimer, and crystal connection for subsystem clock oscillation.(a) INTP0 to INTP6INTP0 to INTP6 are external interrupt request input pins which can specify valid edges (rising edge, fallingedge, and both rising and falling edges). INTP0 or INTP1 becomes a 16-bit timer/event counter capturetrigger signal input pin with a valid edge input.(b) TI00Pin for external count clock input to 16-bit timer/event counter(c) TI01Pin for capture trigger signal to capture register (CR00) of 16-bit timer/event counter(d) XT1Crystal connect pin for subsystem clock oscillation
