Port 7 - NEC 78K0 User Manual

4.2.8

Port 7

Port 7 is an 8-bit I/O port with an output latch. Port 7 can be set to the input mode or output mode in 1-bit units
using port mode register 7 (PM7). When the P70 to P77 pins are used as an input port, use of an on-chip pull-up
resistor can be specified by pull-up resistor option register 7 (PU7).
This port can also be used for key return input.
RESET input sets port 7 to input mode.
Figure 4-19 shows a block diagram of port 7.
WR
PU
RD
WR
PORT
WR
PM
PU7: Pull-up resistor option register 7
PM7: Port mode register 7
RD: Read signal
WR××: Write signal
116
CHAPTER 4 PORT FUNCTIONS
Figure 4-19. Block Diagram of P70 to P77
PU7
PU70 to PU77
Alternate function
Output latch
(P70 to P77)
PM7
PM70 to PM77
User's Manual U15947EJ2V0UD
*
EV
DD
P-ch
P70/KR0 to
P77/KR7