SD6830 Просмотр технического описания (PDF) - AUK -> KODENSHI CORP

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SD6830

4BIT MICROCONTROLLER

AUK -> KODENSHI CORP 

SD6830

6.5 Arithmetic and Logic Unit (ALU)

This unit is used to perform arithmetic and logical operations such as addition,

comparison, and bit manipulation.

6.6 Carry Flag (CY)

The carry flag contains the carry generated by the arithmetic and logical unit immediately

after an operation. The set carry (SETB CY) and clear carry (CLRB CY) instructions allow

direct access for setting and clearing this flag.

6.7 Skip Flag (SF)

The skip flag is a 1-bit register, which enables programs to conditionally skip an instruction.

All instructions are executed when this flag is

, the program executes

NOP instruction and resets SF to “0”. Then program execution proceeds.

The following instructions affect the skip flag

Arithmetic

Compare

Data Transfer

Instructions

ADD n

INC L

IF0 @HL.b

IF0 CY

IFEQU @HL

IFEQU n

STA @HL+

XCH @HL+

Set conditions of SF

If carry occurs

(L) = 0

M[HL].b = 0

(CY) = 0

(A) = M[HL].b

(A) = n

(L) = 0

(L) = 0

The instructions, which doesn t affect the skip flag but have a skip condition, are as follows.

Data

Transfer

Bit

Manipulate

Instructions

LDA n

LDL n

SETB H

CLRB H

Skip conditions

If it is continuous, skip next same

instruction.

If it is continuous, skip next same

instruction.

If SETB H or CLRB H are continuous,

skip next

SETB H or CLRB H instruction.

KSI-W002-000

8

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