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158
7
PA DDR
1
—
0
W
Port A data direction 7 to 0
These bits select input or output for port A pins
7
6
PA DDR
0
W
0
W
6
5
PA DDR
0
W
0
W
5
4
PA DDR
0
W
0
W
4
3
PA DDR
0
W
0
W
3
2
PA DDR
0
W
0
W
2
1
PA DDR
0
W
0
W
1
0
PA DDR
0
W
0
W
0
Bit
Modes
3 and 4
Initial value
Read/Write
Initial value
Read/Write
Modes
1 and 2
The pin functions that can be selected for pins PA
7
to PA
4
differ between modes 1 and 2, and
modes 3 and 4. For the method of selecting the pin functions, see tables 7.12 and 7.13.
The pin functions that can be selected for pins PA
3
to PA
0
are the same in modes 1 to 4. For the
method of selecting the pin functions, see table 7.14.
When port A functions as an input/output port, a pin in port A becomes an output port if the
corresponding PADDR bit is set to 1, and an input port if this bit is cleared to 0. In modes 3 and 4,
PA
7
DDR is fixed at 1 and PA
7
functions as the A
20
address output pin.
PADDR is a write-only register. Its value cannot be read. All bits return 1 when read.
PADDR is initialized to H'00 by a reset and in hardware standby mode in modes 1 and 2. It is
initialized to H'80 by a reset and in hardware standby mode in modes 3 and 4. In software standby
mode it retains its previous setting. Therefore, if a transition is made to software standby mode
while port A is functioning as an input/output port and a PADDR bit is set to 1, the corresponding
pin maintains its output state.
Port A Data Register (PADR): PADR is an 8-bit readable/writable register that stores output
data for port A. When port A functions as an output port, the value of this register is output. When
a bit in PADDR is set to 1, if port A is read the value of the corresponding PADR bit is returned.
When a bit in PADDR is cleared to 0, if port A is read the corresponding pin logic level is read.
Bit
Initial value
Read/Write
0
PA
0
R/W
0
1
PA
0
R/W
1
2
PA
0
R/W
2
3
PA
0
R/W
3
4
PA
0
R/W
4
5
PA
0
R/W
5
6
PA
0
R/W
6
7
PA
0
R/W
7
Port A data 7 to 0
These bits store data for port A pins
PADR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
Summary of Contents for H8/3008
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