UPD78F9418A NEC, UPD78F9418A Datasheet - Page 86

• Manufacturer Part Number: UPD78F9418A
• Description: (UPD7894xxA) 8-Bit Single Chip Microcontrollers
• Manufacturer: NEC

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Note PU0 selects whether on-chip pull-up resistors are to be used in 8-bit units, except for port 0, for which on-
Caution Bits 1, 2, 3, 5, 6, and 7 must be fixed to 0.
Symbol
PM0
PM2
PM4
PM5
PM8
PM9
Symbol
Pull-up resistor option registers (PU0 to PU2)
The pull-up resistor option registers (PU0 to PU2) set whether an on-chip pull-up resistor is used on each
port.
On a port specified by PU0 to PU2 to use an on-chip pull-up resistor, the pull-up resistor can be internally
used only for the bits set in the input mode. No on-chip pull-up resistors can be used for the bits set in the
output mode regardless of the setting of PU0 to PU2. This also applies when using the pins for alternate
functions.
PU0 to PU2 are set using a 1-bit or 8-bit memory manipulation instruction.
RESET input sets PU0 to PU2 to 00H.
PU0
chip pull-up resistors can be used only for four bits (P00 to P03).
PMmn
PM27
PM47
PM87
7
1
1
1
0
1
PU0m
PM46
PM86
PM26
7
0
0
1
Output mode (output buffer on)
Input mode (output buffer off)
6
1
1
1
On-chip pull-up resistor not used
On-chip pull-up resistor used
PM45
PM85
PM25
6
0
1
1
5
1
Figure 4-16. Format of Pull-Up Resistor Option Register 0
5
0
PM44
PM84
PM24
4
1
1
1
PU04
<4>
Figure 4-15. Format of Port Mode Register
PM43
PM83
PM03
PM23
PM53
PM93
3
3
0
CHAPTER 4 PORT FUNCTIONS
PM02
PM22
PM42
PM52
PM82
PM92
2
User’s Manual U13952EJ3V0UD
2
0
PM51
PM91
PM01
PM21
PM41
PM81
Pmn pin I/O mode selection
1
m = 0, 5, 9: n = 0 to 3
m = 2, 4, 8: n = 0 to 7
Pm on-chip pull-up resistor selection
1
0
PM40
PM80
PM00
PM20
PM50
PM90
0
PU00
<0>
(m = 0 or 4)
Address
FF25H
FF29H
FF20H
FF22H
FF24H
FF28H
Address
FFF7H
After reset
After reset
FFH
FFH
FFH
FFH
FFH
FFH
00H
Note
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W