CHAPTER 14 PORT FUNCTIONS
703
User’s Manual U14492EJ3V0UD
14.3.6 Port DH
Port DH is an 8-bit I/O port in which input or output can be specified in 1-bit units.
7
PDH7
PDH
6
PDH6
5
PDH5
4
PDH4
3
PDH3
2
PDH2
1
PDH1
0
PDH0
Address
FFFFF006H
Initial value
Undefined
Bit Position
Bit Name
Function
7 to 0
PDHn
(n = 7 to 0)
I/O port
Besides functioning as a port, in control mode, this can operate as an address bus when memory is expanded
externally.
(1) Operation in control mode
Port
Alternate Pin Name
Remarks
Block Type
Port DH
PDH7 to
PDH0
A23 to A16
Memory expansion address bus
P
(2) Setting in I/O mode and control mode
Port DH is set in I/O mode using the port DH mode register (PMDH). In control mode, it is set using the port
DH mode control register (PMCDH).
(a) Port DH mode register (PMDH)
This register can be read/written in 8-bit or 1-bit units.
7
PMDH7
PMDH
6
PMDH6
5
PMDH5
4
PMDH4
3
PMDH3
2
PMDH2
1
PMDH1
0
PMDH0
Address
FFFFF026H
Initial value
FFH
Bit Position
Bit Name
Function
7 to 0
PMDHn
(n = 7 to 0)
Specifies input/output mode of PDHn pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)
Содержание V850E/IA1 mPD703116
Страница 2: ...2 User s Manual U14492EJ3V0UD MEMO...