NEC mPD784225 Series User Manual page 118

5.2.4 Port 3
Port 3 is an 8-bit I/O port with output latch. The P30 to P37 pins can specify the input mode/output mode in 1-
bit units with the port 3 mode register. A pull-up resistor can be connected via pull-up resistor option register 3,
regardless of whether the input mode or output mode is specified.
Port 3 supports timer input/output as an alternate function.
RESET input sets port 3 to the input mode.
Figures 5-8 and 5-9 show a block diagram of port 3.
WR
PU
RD
WR
PORT
(P30 to P32, P37)
WR
PM
PM30 to PM32,
Alternate function
PU: Pull-up resistor option register
PM: Port mode register
RD: Port 3 read signal
WR: Port 3 write signal
118
CHAPTER 5 PORT FUNCTIONS
Figure 5-8. Block Diagram of P30 to P32, and P37
PU30 to PU32,
PU37
Selector
Output latch
PM37
User's Manual U12697EJ3V0UM
V
DD
P-ch
P30/TO0 to
P32/TO2,
P33/TI1,
P37/EXA