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1-12
3802 GROUP USER’S MANUAL
HARDWARE
FUNCTIONAL DESCRIPTION
CPU Mode Register
The CPU mode register is allocated at address 003B
16
. The CPU mode
register contains the stack page selection bit.
Fig. 9. Structure of CPU mode register
CPU mode register
(
CPUM : address
003B
16
)
Processor mode bits
b1 b0
0 0 : Single-chip mode
0 1 : Memory expansion mode
1 0 : Microprocessor mode
1 1 : Not available
b7
b0
Stack page selection bit
0 : 0 page
1 : 1 page
Not used (return “0” when read)