MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
Structure of Register
The figure of each register structure describes its functions, contents
at reset, and attributes as follows:
Note : The following registers are the EPROM version’s registers.
They are different from the MASK version’s.
Bits
Bit attributes(Note 2)
CPU Mode Register
(Note 1)
Values immediately after reset release
b7b6 b5b4b3 b2b1b0
1 1 0 0
CPU mode register (CPUM) (CM) [Address FB 16
]
B
Name
Functions
After reset R W
Processor mode bits
(CM0, CM1)
b1 b0
0, 1
0
R W
0 0: Single-chip mode
0 1:
1 0:
1 1:
Not available
0: 0 page
1: 1 page
Stack page selection
bit (Note) (CM2)
2
0
1
R W
3, 4 Fix these bits to “1.”
R W
R W
5
Nothing is assigned.1This bit is write disable bit.
When this bit is read out, the value is “0.”
Clock switch bits
(CM6, CM7)
b7 b6
6, 7
0
R W
0 0: f(XIN) = 8 MHz
0 1: f(XIN) = 12 MHz
1 0: f(XIN) = 16 MHz
1 1: Do not set
: Bit in which nothing is assigned
Notes 1: Values immediately after reset release
0••••••“0” after reset release
1••••••“1” after reset release
?••••••Indeterminate after reset release
2: Bit attributes••••••The attributes of control register bits are classified into 3 types : read-only, write-only
and read and write. In the figure, these attributes are represented as follows :
R••••••Read
••••••Read enabled
••••••Read disabled
W••••••Write
••••••Write enabled
✕
••••••Write disabled
✕
••••••“0” can be set by software, but “1”
cannot be set.
✽
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RENESAS [ RENESAS TECHNOLOGY CORP ]
