HD64F3437TF16 Datasheet, PDF (200/752 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.

(1) Upper byte write
CPU writes
data H'AA
Bus
interface
Module data bus
TEMP
[H'AA]
(2) Lower byte write
CPU writes
data H'55
Bus
interface
FRCH
[]
FRCL
[]
Module data bus
TEMP
[H'AA]
FRCH
[H'AA]
FRCL
[H'55]
Figure 8.3 (a) Write Access to FRC (when CPU Writes H'AA55)
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