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CHAPTER 4 PORT FUNCTIONS
User’s Manual U15104EJ2V0UD
(2) Pull-up resistor option register 4 (PU4)
This register is used to specify the use of the internal pull-up resistors of port 4. A pull-up resistor can only
be used internally for the bit specified by PU4.
PU4 can be set with a 1-bit or 8-bit memory manipulation instruction.
Reset input sets PU4 to 00H.
Figure 4-21. Format of Pull-up Resistor Option Register 4 (PU4)
PU4n
Selection of internal pull-up resistor for P4n (n = 0 to 7)
0
Internal pull-up resistor not used
1
Internal pull-up resistor used
Symbol
PU4
7
PU47
6
PU46
5
PU45
4
PU44
3
PU43
2
PU42
1
PU41
0
PU40
Address
FF34H
After reset
00H
R/W
R/W
Содержание mPD178053
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