Hitachi H8/3937 Series Hardware Manual page 183

1. Port data register 9 (PDR9)
Bit 7
—
Initial value 0
Read/Write —
PDR9 is an 8-bit register that stores data for port 9 pins P9
bits are set to 1, the values stored in PDR9 are read, regardless of the actual pin states. If port 9 is
read while PCR9 bits are cleared to 0, the pin states are read.
Upon reset, PDR9 is initialized to H'F0.
2. Port control register 9 (PCR9)
Bit 7
—
Initial value 1
Read/Write —
PCR9 is an 8-bit register for controlling whether each of the port 9 pins P9
input pin or output pin. Setting a PCR9 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin.
Upon reset, PCR9 is initialized to H'F0.
PCR9 is a write-only register, which is always read as all 1s.
6 5 4
— — —
0 0 0
— — —
6 5 4
— — —
1 1 1
— — —
3 2
P9 P9
3 2
0 0
R/W R/W R/W
to P9 . If port 9 is read while PCR9
3 0
3 2
PCR9 PCR9 PCR9
3 2
0 0
W W
to P9
3
1 0
P9 P9
1 0
0 0
R/W
1 0
PCR9
1 0
0 0
W W
functions as an
0
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