HD64F3437TF16 Datasheet, PDF (716/752 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.

C.4 Port 4 Block Diagrams
P4_n
Reset
Q
R
D
P4_nDDR
C
WP4D
Reset
R
QD
P4_nDR
C
WP4
RP4
WP4D: Write to P4DDR
WP4: Write to port 4
RP4: Read port 4
n = 0, 2
8-bit timer
Counter clock input
Counter reset input
Figure C.4 (a) Port 4 Block Diagram (Pins P4₀, P4₂)
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