Microprocessors and Microcontrollers 18th Aug.

Chunk Of Data Transfer from one memory region to another

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XRA A

MVI E,OAH

LXI H,2000H

LXI B,7000H

XX: LDAX H

STAX B

INX B

DCR E

JNZ XX

HLT

Some points

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LDAX H

Now from LXI H,2000H

It is clear that H,L pair contain address 2000H

So, Accumulator Stores the value at address 2000H

I/O

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Two Types

(i) Memory Mapped I/O

(ii) I/O Mapped I/O

Memory Mapped I/O

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Scope of I/O is from Memory itself

Address-16bit

Ex- STA,LDA

I/O Mapped I/O

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I/O selection scope from external peripherals

Address-8bit

Ex- IN,OUT

IN 01H

Means....Input from 01H Port address to the accumulator

OUT 01H

Means.....Output to 01H Port address from the accumulator

Total Port Addresses: 256