UPD784938 Datasheet, PDF (162/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.7 Port 5
Port 5 is an 8-bit input/output port with an output latch. Input/output can be specified in 1-bit units by setting the port 5 mode
register (PM5). Each pin incorporates a software programmable pull-up resistor. This port has direct LED drive capability.
In addition, P50 to P57 function as the address bus (A8 to A15) when external memory or I/Os are expanded.
When RESET is input, port 5 is set as an input port (output high-impedance state), and the output latch contents are undefined.
6.7.1 Hardware configuration
The port 5 hardware configuration is shown in Figure 6-44.
Figure 6-44. Port 5 Block Diagram
WRPUOL
Pull-up resistor option register L
PUOL5
RDPUOL
VDD
MM0 to MM3
WRPM5
Port 5 mode register
RDPM5
PM5n
Internal
data
bus
WRP5
RDP5
Output latch
P5n
P5n
n = 0 to 7
Input/
output
control
circuit
Internal
address
bus
162
Preliminary User’s Manual U13987EJ1V0UM00