HD64F3437TF16 Datasheet, PDF (666/752 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.

RDR—Receive Data Register
H'8D
SCI1
Bit
7
6
5
4
3
2
1
0
Initial value
0
0
0
0
0
0
0
0
Read/Write
R
R
R
R
R
R
R
R
Receive data
637