STC89LE53RC datasheet(64/165 Pages) STC

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MOV

DPTR , #data 16

Function:

Load Data Pointer with a 16-bit constant

Description:

The Data Pointer is loaded with the 16-bit constant indicated.The 16-bit constant is loaded

into the second and third bytes of the instruction. The second byte (DPH) is the high-order

byte, while the third byte (DPL) holds the low-order byte. No flags are affected.

This is the only instruction which moves 16 bits of data at once.

Example:

The instruction,

MOV

DPTR, #1234H

will load the value 1234H into the Data Pointer: DPH will hold 12H and DPL will hold 34H.

Bytes:

Cycles:

Encoding:

1 0 0

0 0 0 0

immediate data 15-8

Operation:

MOV

(DPTR) ← #data

← #data

#data

15-0

DPH DPL ← #data

← #data

15-8 #data7-0

MOVC

A , @A+ <base-reg>

Function:

Move Code byte

Description:

The MOVC instructions load the Accumulator with a code byte, or constant from program

memory. The address of the byte fetched is the sum of the original unsigned eight-bit.

Accumulator contents and the contents of a sixteen-bit base register, which may be either

the Data Pointer or the PC. In the latter case, the PC is incremented to the address of the

following instruction before being added with the Accumulator; otherwise the base register

is not altered. Sixteen-bit addition is performed so a carry-out from the low-order eight bits

may propagate through higher-order bits. No flags are affected.

Example:

A value between 0 and 3 is in the Accumulator. The following instructions will translate the

value in the Accumulator to one of four values defimed by the DB (define byte) directive.

REL-PC: INC

MOVC A, @A+PC

RET

66H

77H

88H

99H

If the subroutine is called with the Accumulator equal to 01H, it will return with 77H in the

Accumulator. The INC A before the MOVC instruction is needed to “get around” the RET

instruction above the table. If several bytes of code separated the MOVC from the table, the

corresponding number would be added to the Accumulator instead.

MOVC A,@A+DPTR

Bytes:

Cycles:

Encoding:

1 0 0 1

0 0 1 1

Operation:

MOVC

(A) ← ((A)+(DPTR))

← ((A)+(DPTR))

((A)+(DPTR))

STC89LE53RC Datenblatt(PDF) 64 Page - STCmicro Technology Co,.Ltd

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