NEC PD78F9488 User Manual
Page 93
CHAPTER 4 PORT FUNCTIONS
User’s Manual U15331EJ4V1UD
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 via 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 0 0 0 0 0
PUB11
PUB10
FF31H
00H
R/W
7
6 <5> <4> <3> <2> <1> <0>
PUB2
0
0
PUB25 PUB24 PUB23 PUB22 PUB21 PUB20 FF32H
00H R/W
7
6
5 <4> <3> <2> <1> <0>
PUB3
0
0
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) (
µPD78F9488, 78F9489 only)
These registers specify in 1-bit units whether to use P70 to P73 and P80 to P87 as port pins or segment
outputs.
PF7 and PF8 are set via a 1-bit or 8-bit memory manipulation instruction.
RESET input sets these registers to 00H.
Caution This register is valid only in the
µPD78F9488 and 78F9489; however, writing to it in the
µPD789488 and 789489 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 0 0 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.