MB90480/485 Series
(2) Port Direction Registers
DDR0
Initial value Access
7
6
5
4
3
2
1
0
Address : 000010H
00000000B
00000000B
00000000B
00000000B
00000000B
00000000B
00000000B
R/W
R/W
R/W
R/W
R/W
R/W
R/W
D07
D06
D05
D04
D03
D02
D01
D00
DDR1
7
6
5
4
3
2
1
0
Address : 000011H
D17
D16
D15
D14
D13
D12
D11
D10
DDR2
7
6
5
4
3
2
1
0
Address : 000012H
D27
D26
D25
D24
D23
D22
D21
D20
DDR3
7
6
5
4
3
2
1
0
Address : 000013H
D37
D36
D35
D34
D33
D32
D31
D30
DDR4
7
6
5
4
3
2
1
0
Address : 000014H
D47
D46
D45
D44
D43
D42
D41
D40
DDR5
7
6
5
4
3
2
1
0
Address : 000015H
D57
D56
D55
D54
D53
D52
D51
D50
DDR6
7
6
5
4
3
2
1
0
Address : 000016H
D67
D66
D65
D64
D63
D62
D61
D60
DDR7
7
6
5
4
3
2
1
0
D76*1
D77*1
Address : 000017H
00000000B*2 R/W
D75
D74
D73
D72
D71
D70
DDR8
7
6
5
4
3
2
1
0
Address : 000018H
00000000B
00000000B
----0000B
R/W
R/W
R/W
D87
D86
D85
D84
D83
D82
D81
D80
DDR9
7
6
5
4
3
2
1
0
Address : 000019H
D97
D96
D95
D94
D93
D92
D91
D90
DDRA
7
6
5
4
3
2
1
0
Address : 00001AH
⎯
⎯
⎯
⎯
DA3
DA2
DA1
DA0
*1 : The value is set to “⎯” on MB90485 series only.
*2 : The initial value of this bit is “XX000000B” on MB90485 series only.
• When a set of pins is functioning as a port, the corresponding signal pins are controlled as follows.
0 : Input mode.
1 : Output mode. Reset to “0”.
Notes : • When any of these registers are accessed using a read-modify-write type instruction (such as a bit set
instruction) , the bit specified in the instruction will be set to the indicated value. However, the contents
of output registers corresponding to any other bits having input settings will be rewritten to the input values
of those pins at that time.
For this reason, when changing any pin that has been used for input to output, first write the desired value
to the PDR register before setting the DDR register for output.
• P76, P77 (MB90485 series only)
This port has no DDR. To use P77 and P76 as I2C pins, set the PDR value to “1” so that port data remains
enabled (to use P77 and P76 for general purposes, disable I2C) . The port is an open drain output (with
no P-ch) .
To use it as an input port, therefore, set the PDR to “1” to turn off the output transistor and add a pull-up
resistor to the external output.
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