Port 12 - NEC 78K0 User Manual

4.2.7 Port 12

Port 12 is a 1-bit I/O port with an output latch. Port 12 can be set to the input mode or output mode in 1-bit units
using port mode register 12 (PM12). When used as an input port, use of an on-chip pull-up resistor can be specified
by pull-up resistor option register 12 (PU12).
This port can also be used for external interrupt input.
RESET input sets port 12 to input mode.
Figure 4-14 shows a block diagram of port 12.
WR
PU
RD
WR
PORT
WR
PM
PU12: Pull-up resistor option register 12
PM12: Port mode register 12
RD: Read signal
WR××: Write signal
90
CHAPTER 4 PORT FUNCTIONS
Figure 4-14. Block Diagram of P120
PU12
PU120
Alternate
function
Output latch
(P120)
PM12
PM120
User's Manual U16227EJ2V0UD
EV
DD
P-ch
P120/INTP0