UPD784938 Datasheet, PDF (174/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 6 PORT FUNCTIONS
6.8.2 I/O mode/control mode setting
The port 6 input/output mode is set by setting the port 6 mode register (PM6) as shown in Figure 6-55.
Operations for operating port 6 as control pins are shown in Table 6-9.
Table 6-9. Port 6 Control Pin Function
Pin Name
P60
P61
P62
P63
P64
P65
P66
P67
Control Signal I/O Mode
A16
A17
A18
A19
RD
WR
WAIT
HLDRQ
HLDAK
REFRQ
Port Mode
Input/output port
Operation to Operate as Control Pins
External memory expansion mode specified by bits MM3 to MM0 of
the MM (see Table 6-10)
Output port
External memory expansion mode specified by bits MM3 to MM0 of
the MM (see Table 6-10)
Input/output port
Output port
External wait input is specified by bits
PWn1 & PWn0 (n = 0 to 7) of the PWC1 & PWC2
Bus hold enabled by the HLDE bit of the HLDM
Set (to 1) the RFEN bit of the RFM
Table 6-10. P60 to P65 Control Pin Specification
MM Bits
Operation Mode
MM3
MM2
MM1
MM0
P60
P61
P62
P63
P64
P65
0
0
0
0
Port (P60 to P65)
0
0
1
1
0
1
0
0
Port (P60 to P63)
RD
WR
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
A16
A17
Port
1
0
0
1
A16
A17
A18
A19
(a) Port mode
Each port not specified as in control mode can be specified as input/output in 1-bit units by setting the port 6 mode
register (PM6).
(b) Control signal input/output mode
(i) A16 to A19 (Address Bus)
Upper address bus output pins when the external memory space is expanded (10000H to FFFFFH).
These pins operate in accordance with the memory expansion mode register (MM).
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Preliminary User’s Manual U13987EJ1V0UM00