3 special function register (sfr) addressing – NEC switch User Manual
Page 53
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CHAPTER 3 CPU ARCHITECTURE
User’s Manual U12978EJ3V0UD
53
3.4.3 Special function register (SFR) addressing
[Function]
The memory-mapped special function register (SFR) is addressed with 8-bit immediate data in an instruction
word.
This addressing is applied to the 240-byte spaces FF00H to FFCFH and FFE0H to FFFFH. However, the
SFR mapped at FF00H to FF1FH can be accessed with short direct addressing.
[Operand format]
Identifier
Description
sfr
Special function register name
[Description example]
MOV PM0, A; When selecting PM0 for sfr
Instruction code
1
1
1
0
0
1
1
1
0
0
1
0
0
0
0
0
[Illustration]
15
0
SFR
Effective
Address
1
1
1
1
1
1
1
8 7
0
7
Opcode
sfr-offset
1
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