HD404818 Datasheet, PDF (17/100 Pages) Hitachi Semiconductor – 16-digit LCD driver

HD404818 Series
Functional Description
Registers and Flags
The MCU provides ten registers and two flags for CPU operations. They are illustrated in figure 5 and
described in the following paragraphs.
Accumulator
Initial value: Undefined, R/W
3
0
(A)
B register
V register
W register
X register
Y register
Initial value: Undefined, R/W
Initial value: 0, R/W
Initial value: Undefined, R/W
Initial value: Undefined, R/W
Initial value: Undefined, R/W
3
0
(B)
0
(V)
10
(W)
3
0
(X)
3
0
(Y)
SPX register
Initial value: Undefined, R/W
SPY register
Initial value: Undefined, R/W
Carry
Initial value: Undefined, R/W
Status
Initial value: 1, no R/W
Program counter
13
Initial value: 0,
no R/W
Stack pointer
Initial value: $3FF, no R/W
(PC)
9
5
1 11 1
3
0
(SPX)
3
0
(SPY)
0
(CA)
0
(ST)
0
0
(SP)
Figure 5 Registers and Flags
Accumulator (A), B Register (B): The accumulator and B register are 4-bit registers which hold the
results of the arithmetic logic unit (ALU), and exchange data between memory, I/O, and other registers.
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