Fujitsu MB90390 Series Hardware Manual page 648

APPENDIX
• "X" indicates an undefined value.
• Any write access to reserved addresses in I/O map should not be performed.
A read access to reserved address results in reading "X".
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Explanation of write and read
R/W: Both read and write enabled
R: Only read enabled
W: Only write enabled
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Explanation of initial values
0: The initial value of this bit is "0".
1: The initial value of this bit is "1".
X: The initial value of this bit is undefined.
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