UPD784938 Datasheet, PDF (194/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.11.3 Operating status
Port 10 is an input/output port, with an alternate function as various control pins.
(1) When set as an output port
The output latch is enabled, and data transfers between the output latch and accumulator are performed by means of
transfer instructions. The output latch contents can be freely set by means of logical operation instructions. Once data has
been written to the output latch, it is retained until data is next written to the output latch^Note.
Note Including the case where another bit of the same port is manipulated by a bit manipulation instruction.
Figure 6-76. Port Specified as Output Port
WRPORT
Internal
bus
RDOUT
Output
latch
P10n
n = 0 to 7
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Preliminary User’s Manual U13987EJ1V0UM00