HD404328US View Datasheet(PDF) - Renesas Electronics

Part Name

Description

Manufacturer

HD404328US

4-bit HMCS400-series microcomputer

Renesas Electronics 

HD404328 Series

Functional Description

Registers and Flags

The MCU has nine registers and two flags for CPU operations. They are shown in figure 5 and described

below.

Accumulator

Initial value: Undefined, R/W

3

0

(A)

B register

Initial value: Undefined, R/W

3

0

(B)

W register

Initial value: Undefined, R/W

10

(W)

X register

Initial value: Undefined, R/W

3

0

(X)

Y register

Initial value: Undefined, R/W

3

0

(Y)

SPX register

Initial value: Undefined, R/W

3

0

(SPX)

SPY register

Initial value: Undefined, R/W

3

0

(SPY)

Carry

Initial value: Undefined, R/W

0

(CA)

0

Status

Initial value: 1, no R/W

(ST)

Program counter

13

Initial value: 0,

no R/W

Stack pointer

Initial value: $3FF, no R/W

0

(PC)

9

5

0

1 11 1

(SP)

Figure 5 Registers and Flags

Accumulator (A), B Register (B): Four-bit registers used to hold results from the arithmetic logic unit

(ALU) and transfer data between memory, I/O, and other registers.

13

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