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8.2.3
Other registers
This section shows the configuration and explains the functions of registers other
than port registers (PDR0 to PDRA) or port direction registers (DDR0 to DDRA).
■
Port input resistor registers (RDR0, RDR1)
The bit configuration of port input resistor registers (RDR0, RDR1) is shown in the figure below.
RDR0
Address:00001C
RDR1
Address:00001D
R/W : Readable/Writable
Port input resistor registers (RDR0, RDR1) specify whether or not there is pull-up resistor in the
input mode.
•
0: Pull-up resistor in the input mode
•
1: No pull-up resistor in the input mode
These registers have no function in the output mode (no pull-up resistor).
The input or output mode is determined by the setting on the port direction register (DDR).
During a stoppage (SPL = 1), the lack of pull-up resistor is specified (high impedance).
This function is prohibited if an external bus is used. Do not write to this register.
■
Port output pin registers (ODR7, ODR4)
The bit configuration of port output pin registers (ODR7, ODR4) is shown in the figure below.
ODR7
Address:00001E
H
ODR4
Address:00001B
H
*1: The value of bit7 for
*2: The value of bit6 for
*3: The initial value of
Port output pin registers (ODR7, ODR4) perform open drain control in the output mode.
•
0: Sets a standard output port in the output mode
•
1: Sets an open-drain output port in the output mode
Port output pin registers (ODR7, ODR4) have no function in the input mode (Output Hi-Z).
The input or output mode is determined by the setting of the port direction register (DDR).
This function is prohibited when an external bus is used. Do not write to this register.
7
6
5
RD07 RD06 RD05 RD04 RD03 RD02 RD01 RD00
H
7
6
5
RD17 RD16 RD15 RD14 RD13 RD12 RD11 RD10
H
7
6
5
4
*1
*2
OD77
OD76
OD75 OD74 OD73 OD72 OD71 OD70
7
6
5
4
OD47 OD46 OD45 OD44 OD43 OD42 OD41 OD40
MB90485 series is "-".
only
MB90485 series is "-".
only
MB90485 series is "XX000000
only
4
3
2
1
4
3
2
1
3
2
1
0
3
2
1
0
".
B
CHAPTER 8 I/O PORT
0
Initial value Access
00000000
R/W
B
0
00000000
R/W
B
Initial value
Access
*3
00000000
R/W
B
00000000
R/W
B
R/W : Readable/Writable
183
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