HD6433937 Datasheet, PDF (167/521 Pages) Hitachi Semiconductor – Hardware Manual

1. Port data register 4 (PDR4)
Bit
7
6
5
4
3
2
1
0
—
—
—
—
P4₃
P4 ₂
P4 ₁
P4 ₀
Initial value
1
1
1
1
1
0
0
0
Read/Write
—
—
—
—
R
R/W
R/W
R/W
PDR4 is an 8-bit register that stores data for port 4 pins P4₂ to P4₀. If port 4 is read while PCR4
bits are set to 1, the values stored in PDR4 are read, regardless of the actual pin states. If port 4 is
read while PCR4 bits are cleared to 0, the pin states are read.
Upon reset, PDR4 is initialized to H'F8.
2. Port control register 4 (PCR4)
Bit
7
6
5
4
3
2
1
0
—
—
—
—
— PCR4₂ PCR4₁ PCR4 ₀
Initial value
1
1
1
1
1
0
0
0
Read/Write
—
—
—
—
—
W
W
W
PCR4 is an 8-bit register for controlling whether each of port 4 pins P4₂ to P4₀ functions as an
input pin or output pin. Setting a PCR4 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin. PCR4 and PDR4 settings are valid when the
corresponding pins are designated for general-purpose input/output by SCR3-2.
Upon reset, PCR4 is initialized to H'F8.
PCR4 is a write-only register, which always reads all 1s.
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