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CHAPTER 3 REGISTERS
3.7 Direct Banks
The direct bank is in 0080
H
to 047F
H
of direct area, and composed of 128 bytes × 8
banks. The access that uses direct addressing and bit direct addressing in operand
address 80
H
to FF
H
can be extended to 8 direct banks according to the value of the
direct bank pointer (DP). The current bank is indicated by the direct bank pointer (DP).
■ Direct Bank
Figure 3.7-1 shows the configuration of a direct bank.
The access that uses direct addressing and bit direct addressing in operand address 80
H
to FF
H
can be
extended to 8 direct banks according to the value of the direct bank pointer (DP). The access that uses
direct addressing and bit direct addressing in operand address 00
H
to 7F
H
is not affected by the value of the
direct bank pointer (DP). This access is directed to fixed direct area 0000
H
to 007F
H
.
Figure 3.7-1 Configuration of Direct Bank
Direct area
Memory
047F
H
0400
H
017F
H
0100
H
00FF
H
0080
H
007F
H
0000
H
Direct bank 7
(DP=111)
Direct bank 1
(DP=001)
Direct bank 0
(DP=000)
Fixed direct area
FF
H
80
H
7F
H
00
H
Direct addressing
and
Operand address
in bit direct addressing