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CHAPTER 8 I/O PORT
8.2 I/O Port Register
8.2.3
Other Registers
The configuration and functions of the register other than the port data register (PDR0
to PDR2, PDR4 to PDR6) and the port direction register (DDR0 to DDR2, DDR4 to DDR6)
are described.
■ Port 0, 1 Pull-up Resistor Register (RDR0,RDR1)
Figure 8.2-3 shows the bit configuration of the pull-up resistor register (RDR0, RDR1).
Figure 8.2-3 Bit Configuration of Pull-up Resistor Register (RDR0,RDR1)
RDR0
00001C
Address :
RDR1
00001D
Address :
The pull-up resistor register (RDR0, RDR1) determines whether the pull-up resistor is enabled or not in the
input mode.
• 0: There is not a pull-up resistor none at input mode
• 1: There is a pull-up resistor at the input mode.
The RDR0 and RDR1 registers do not have any function in the output mode (no pull-up resistor).
The input/output register is decided by the setting of the direction register (DDR).
There is no pull-up resistor at the time of stop (SPL=1) (high impedance).
This function is disable for the external bus. Be sure not to write into the RDR0 and RDR1 registers.
■ Port 4 Output Pin Register (ODR4)
Figure 8.2-4 shows the bit configuration of the output pin register (ODR4).
ODR4
00001B
Address :
The output pin register (ODR4) executes open drain control in the output mode.
• 0: Entering in the standard output port in the output mode
• 1: Entering in the open drain output port in the output mode
The output pin register (ODR4) does not have it function in the input mode (Output of Hi-Z).
The input/output mode is decided by the setting of the direction register (DDR).
This function is disable for the external bus. Do not write to the output pin register (ODR4).
168
bit
7
6
5
RD07 RD06 RD05 RD04 RD03 RD02 RD01 RD00
H
bit
15
14
13
RD17 RD16 RD15 RD14 RD13 RD12 RD11 RD10
H
Figure 8.2-4 Bit Configuration of Output Pin Register (ODR4)
15
14
13
bit
OD47 OD46 OD45 OD44 OD43 OD42 OD41 OD40
H
FUJITSU MICROELECTRONICS LIMITED
4
3
2
1
12
11
10
9
12
11
10
9
MB90335 Series
0
Initial value
Access
00000000
R/W
B
8
R/W
00000000
B
8
Initial value
Access
00000000
R/W
B
CM44-10137-6E
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