Port Dl - NEC UPD703116 User Manual

14.3.7 Port DL

Port DL is a 16-bit or 8-bit I/O port in which input or output can be specified in 1-bit units.
When using the higher 8 bits of PDL as PDLH and the lower 8 bits as PDLL, it can be used as an 8-bit I/O port that
can specify input or output in 1-bit units.
15 14
PDL PDL15 PDL14
7 6
PDL7 PDL6
Bit position Bit name
15 to 0 PDLn
(n = 15 to 0)
Besides functioning as a port, in control mode, this can operate as an address/data bus when memory is expanded
externally.
(1) Operation in control mode
Port
Port DL PDL15 to
PDL0
(2) Setting in I/O mode and control mode
Port DL is set in I/O mode using the port DL mode register (PMDL). In control mode, it is set using the port
DL mode control register (PMCDL).
702
CHAPTER 14 PORT FUNCTIONS
13 12 11
PDL13 PDL12 PDL11
5 4 3
PDL5 PDL4 PDL3
I/O port
Alternate Pin Name
AD15 to AD0 Memory expansion address/data bus
User's Manual U14492EJ5V0UD
10 9 8
PDL10 PDL9 PDL8
2 1 0
PDL2 PDL1 PDL0
Function
Remarks
Address Initial value
FFFFF005H Undefined
Address
FFFFF004H
Block Type
O