NEC PD78F9488 Manuale Utente

CHAPTER  4   PORT  FUNCTIONS 

User’s Manual  U15331EJ4V1UD

This is a 5-bit I/O port with an output latch.  Port 3 can be specified in the input or output mode in 1-bit units by 

using port mode register 3 (PM3).  When using the P30 to P34 pins as input port pins, on-chip pull-up resistors can be 
connected in 1-bit units by using pull-up resistor option register B3 (PUB3). 

This port is also used for external interrupt input, capture input, timer I/O, and remote control receive data input

. 

RESET input sets this port to input mode. 
Figures 4-9 and 4-10 show block diagrams of port 3. 
 

Note 

µ

 PD789489 and 78F9489 only 

 

 

 

PUB3:  Pull-up resistor option register B3 
PM: 

Port mode register 

RD: 

Port 3 read signal 

WR: 

Port 3 write signal 

 

P30/INTP0/TO50/
TMI60,
P31/INTP1/TO60, 
P32/INTP2/TO61/
TMI61
P33/INTP3/TO20/
CPT20

WR

PUB3

RD

WR

PORT

WR

PM

PUB30 to PUB33

PM30 to PM33

V

DD

P-ch

Internal bus

Alternate

function

Selector

Output latch

(P30 to P33)

Alternate

function