MITSUBISHI MICROCOMPUTERS
3822 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
[CPU Mode Register (CPUM)] 003B16
The CPU mode register contains the stack page selection bit and
the internal system clock selection bit.
The CPU mode register is allocated at address 003B16.
b7
b0
CPU mode register
(CPUM (CM) : address 003B16)
Processor mode bits
b1 b0
0
0
1
1
0 : Single-chip mode
1 :
0 :
Not available
1 :
Stack page selection bit
0 : 0 page
1 : 1 page
Not used (returns “1” when read)
(Do not write “0” to this bit)
Port XC switch bit
0 : I/O port function (stop oscillating)
1 : XCIN–XCOUT oscillating function
Main clock (XIN–XOUT) stop bit
0 : Oscillating
1 : Stopped
Main clock division ratio selection bit
0 : f(XIN)/2 (high-speed mode)
1 : f(XIN)/8 (middle-speed mode)
Internal system clock selection bit
0 : XIN–XOUT selected (middle-/high-speed mode)
1 : XCIN–XCOUT selected (low-speed mode)
Fig. 11 Structure of CPU mode register
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MITSUBISHI [ Mitsubishi Group ]
