HD404849 Datasheet, PDF (54/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
Miscellaneous register (MIS: $00C)
Bit
3
2
1
Initial value
0
0
0
Read/Write
Bit name
W
MIS3
W
MIS2
W
MIS1
0
0
W
MIS0
MIS3
0
1
Pull-up MOS
on/off selection
Off
On
MIS2
0
1
CMOS buffer
on/off selection
for pin R2₃/SO
On
Off
MIS1
MIS0
t_RC selection.
Refer to figure 18 in the
operation modes section.
Figure 38 Miscellaneous Register (MIS)
How to Deal with Unused I/O Pins: I/O pins that are not needed by the user system (floating) must be
connected to V_CC to prevent LSI malfunctions due to noise. These pins must either be pulled up to V_CC by
their pull-up MOS transistors or by resistors of about 100 kΩ.
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