Hitachi SH7750 series Hardware Manual page 826

3. Use word-size access when writing. Perform the write with the upper byte set to H'5A or
H'A5, respectively. Byte- and longword-size writes cannot be used.
Use byte-size access when reading.
4. SH7750S only
Rev. 4.0, 04/00, page 819 of 850