HD404829R Datasheet, PDF (58/149 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a LCD controller/Driver Circuit

HD404829R Series
Pull-Up MOS Transistor Control: A program-controlled pull-up MOS transistor is provided for each
input/output pin other than input-only pins D₁₀ and D₁₁. The on/off status of all these transistors is
controlled by bit 3 (MIS3) of the miscellaneous register (MIS: $00C), and the on/off status of an individual
transistor can also be controlled by the port data register (PDR) of the corresponding pin—enabling on/off
control of that pin alone (table 17 and figure 41).
The on/off status of each transistor and the peripheral function mode of each pin can be set independently.
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.
Miscellaneous register (MIS: $00C)
Bit
3
2
1
Initial value
Read/Write
Bit name
0
W
MIS3
0
W
MIS2
0
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 41 Miscellaneous Register (MIS)
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