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[CPU Mode Register (CPUM)] 003B16
The CPU mode register contains the stack page selection bit and
the internal system clock selection bit etc.
The CPU mode register is allocated at address 003B16.
MITSUBISHI MICROCOMPUTERS
38B7 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
b7
Fig. 7 Structure of CPU mode register
b0
CPU mode register
(CPUM: address 003B16)
Processor mode bits
b1b0
0 0 : Single-chip mode
0 1:
1 0 : Not available
1 1:
Stack page selection bit
0 : Page 0
1 : Page 1
Not used (return “1” when read)
(Do not write “0” to this bit.)
Port XC switch bit
0 : I/O port function
1 : XCIN–XCOUT oscillating function
Main clock (XIN–XOUT) stop bit
0 : Oscillating
1 : Stopped
Main clock division ratio selection bit
0 : f(XIN) (high-speed mode)
1 : f(XIN)/4 (middle-speed mode)
Internal system clock selection bit
0 : XIN-XOUT selection (middle-/high-speed mode)
1 : XCIN-XCOUT selection (low-speed mode)
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