M38258MCM Datasheet, PDF (11/70 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3825 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
FUNCTIONAL DESCRIPTION
CENTRAL PPROCESSING UNIT (CPU)
The 3825 group uses the standard 740 family instruction set. Refer
to the 740 Family Software Manual for details on the instruction set.
Machine-resident 740 family instructions are as follows:
The FST and SLW instructions cannot be used.
The STP, WIT, MUL, and DIV instructions can be used.
[CPU Mode Register (CPUM)] 003B16
The CPU mode register is allocated at address 003B16.
The CPU mode register contains the stack page selection bit
and the internal system clock selection bit.
b7
Fig. 8 Structure of CPU mode register
b0
CPU mode register
(CPUM (CM) : address 003B16)
Processor mode bits
b1 b0
0 0 : Single-chip mode
0 1:
1 0 : Not available
1 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)
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