2 MEMORY AND OPERATIONS

2.5.4 Initial reset

On reset, the registers and flags are set as shown in Table 2.5.4.1.

Table 2.5.4.1 Reset value

 

 

Bit length

Value

Program Counter Step

PCS

8

00H

 

 

 

 

Program Counter Page

PCP

4

01H

 

 

 

 

Program Counter Bank

PCB

1

00H

 

 

 

 

New Page Pointer

NPP

4

01H

 

 

 

 

New Bank Pointer

NBP

1

Undefined

 

 

 

 

Stack Pointer

SP

8

Undefined

 

 

 

 

Index Register

IX

12

Undefined

 

 

 

 

Index Register

IY

12

Undefined

 

 

 

 

Register Pointer

RP

4

Undefined

 

 

 

 

General Register

A

4

Undefined

 

 

 

 

General Register

B

4

Undefined

 

 

 

 

Interrupt Flag

I

1

0H

 

 

 

 

Decimal Flag

D

1

*

 

 

 

 

Zero Flag

Z

1

Undefined

 

 

 

 

Carry Flag

C

1

Undefined

 

 

 

 

* S1C6200

...Undefined

S1C6200A

...0

<Difference between S1C6200 and S1C6200A>

There is a difference in the setting value of the D (decimal) flag at initial reset between the S1C6200 and the S1C6200A.

Table 2.5.4.2 D (decimal) flag initial setting

CPU Core

S1C6200A

S1C6200

D (decimal) flag setting

0

Undefined

 

 

 

When using the model loaded with the S1C6200 Core CPU, set or reset the D flag in the user's initial routine before using an arithmetic instruction. (refer to the SDF and RDF instructions.)

S1C6200/6200A CORE CPU MANUAL

EPSON

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