CHAPTER 4 PORT FUNCTIONS
User’s Manual U15400EJ4V0UD
93
(2)
Pull-up resistor option registers (PUB0 to PUB3)
These registers set whether to use on-chip pull-up resistors for pins P00 to P07, P10, P11, P20 to P25, and
P30 to P34. An on-chip pull-up resistor can be used only for those bits set to the input mode in a port for
which the use of the on-chip pull-up resistor has been specified using PUB0 to PUB3.
For those bits set to the output mode, on-chip pull-up resistors cannot be used, regardless of the setting of
PUB0 to PUB3. This also applies to alternate-function pins used as output pins.
PUB0 to PUB3 are set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets these registers to 00H.
Figure 4-16. Format of Pull-Up Resistor Option Registers
Symbol
<7>
<6>
<5>
<4>
<3>
<2>
<1>
<0>
Address
After reset
R/W
PUB0
PUB07
PUB06
PUB05
PUB04
PUB03
PUB02
PUB01
PUB00
FF30H
00H
R/W
7
6
5
4
3
2
<1>
<0>
PUB1
0
PUB11
PUB10
FF31H
00H
R/W
7
6
<5>
<4>
<3>
<2>
<1>
<0>
PUB2
0
PUB25
PUB24
PUB23
PUB22
PUB21
PUB20
FF32H
00H
R/W
7
6
5
<4>
<3>
<2>
<1>
<0>
PUB3
0
PUB34
PUB33
PUB32
PUB31
PUB30
FF33H
00H
R/W
PUBmn
Pmn on-chip pull-up resistor selection
(m = 0 to 3, n = 0 to 7)
0
An on-chip pull-up resistor is not connected.
1
An on-chip pull-up resistor is connected.
(3)
Port function registers (PF7 and PF8) (
μPD78F9478 and 78F9479 only)
These registers specify in 1-bit units whether to use P70 to P73 and P80 to P87 as ports or segment outputs.
PF7 and PF8 are set with 8-bit memory manipulation instruction.
RESET input sets these registers to 00H.
Caution
This register is valid only in the
μPD78F9478 and 78F9479; however, writing to it in the
μPD789477, 789478, and 789479 will simply make it invalid, causing no operational effect.
Figure 4-17. Port Function Register Format
Symbol
7
6
5
4
<3>
<2>
<1>
<0>
Address
After reset
R/W
PF7
0
PF73
PF72
PF71
PF70
FF57H
00H
W
<7>
<6>
<5>
<4>
<3>
<2>
<1>
<0>
PF8
PF87
PF86
PF85
PF84
PF83
PF82
PF81
PF80
FF58H
00H
W
PFmn
Pmn port/segment output specification (m = 7 or 8, n = 0 to 7)
0
Pmn is used as a port pin.
1
Pmn is used as a segment output.