CHAPTER 2 PIN FUNCTIONS
(f) ASCK20
This is the serial clock input pin of the asynchronous serial interface.
Caution When using P20 to P26 as serial interface pins, the I/O mode and output latch must be set
according to the functions to be used. For the details of the setting, refer to Table 12-2 Settings
of Serial Interface 20 Operating Mode.
2.2.4 P30 to P33 (Port 3)
These pins constitute a 4-bit I/O port. In addition, they also function as timer I/O and external interrupt input.
Port 3 can be specified in the following operation mode in 1-bit units.
(1) Port mode
In this mode, P30 to P33 functions as a 4-bit I/O port. Port 3 can be set in the input or output port mode in
1-bit units by port mode register 3 (PM3). When used as an input port, use of an on-chip pull-up resistor can
be specified by pull-up resistor option register B3 (PUB3) in 1-bit units.
(2) Control mode
In this mode, P30 to P33 function as timer I/O and external interrupt input.
(a) TMI60
This is the external clock input pin to timer 60.
(b) TO50, TO60, TO61
These are the timer output pins of timer 50 and timer 60
(c) CPT90
This is the capture edge input pin of 16-bit timer 90.
(d) INTP0 to INTP3
These are external interrupt input pins for which valid edges (rising edge, falling edge, or both rising
and falling edges) can be specified.
2.2.5 P50 to P53 (Port 5)
These pins function as a 4-bit N-ch open-drain I/O port. Port 5 can be set in the input or output port mode in 1-bit
units by port mode register 5 (PM5). In the mask ROM version, use of an on-chip pull-up resistor can be specified by
a mask option.
2.2.6 P60 to P65 (Port 6)
This is a 6-bit input-only port. In addition to a general-purpose input port function, it has an A/D converter input
function.
(1) Port mode
In this mode, P60 to P65 function as 6-bit input-only port.
(2) Control mode
In this mode, P60 to P65 function as analog inputs (ANI0 to ANI5) of A/D converter.
User’s Manual U15075EJ1V0UM00
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NEC [ NEC ]
