HD64F3437TF16 Datasheet, PDF (152/752 Pages) Hitachi Semiconductor – 12 V must not be applied to the S-mask model (single-power-supply specification), as this may permanently damage the device.

Port 4 Data Register (P4DR)
Bit
7
P4₇
Initial value
0
Read/Write R/W
6
P4₆
0
R/W
5
P4₅
0
R/W
4
P4₄
0
R/W
3
P4₃
0
R/W
2
P4₂
0
R/W
1
P4₁
0
R/W
0
P4₀
0
R/W
P4DR is an 8-bit register that stores data for pins P4₇ to P4₀. When a P4DDR bit is set to 1, if port
4 is read, the value in P4DR is obtained directly, regardless of the actual pin state. When a P4DDR
bit is cleared to 0, if port 4 is read the pin state is obtained. This also applies to pins used by on-
chip supporting modules.
P4DR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its existing values.
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