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CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U13420EJ2V0UM00
4.2.6 Port 6
Port 6 is a 4-bit input/output port with output latch. Input mode/output mode can be specified for pins P64 to P67
in 1-bit units with port mode register 6 (PM6). For pins P64 to P67, an on-chip pull-up resistor can be specified in
1-bit units with pull-up resistor option register 6 (PU6).
This port can also be used as a control signal output in external memory expansion mode.
RESET input sets port 6 to input mode.
Figure 4-7 shows a block diagram of port 6.
Caution
When external wait is not used in external memory expansion mode, P66 can be used as an
input/output port.
Figure 4-7. Block Diagram of P64 to P67
PU: Pull-up resistor option register
PM: Port mode register
RD: Port 6 read signal
WR: Port 6 write signal
RD
P64/RD,
P65/WR,
P66/WAIT,
P67/ASTB
P-ch
WR
PU
WR
PORT
WR
PM
PU64 to PU67
Output latch
(P64 to P67)
PM64 to PM67
Selector
V
DD0
Internal bus
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