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Memory interfacing with 8086

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Physical memory organisation

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Semiconductor memories are of two types

RAM(random access memory)

ROM(read only memory)

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The general procedure of static memory interfacingwith 8086 is described as follows:

1.Arrange the available memory chips so as to obtain

16-bit data bus width.2.The upper 8-bit bank is called odd address bank and

lower 8-bit bank is called even address bank.

3.Connect available address lines of memory chips with

those of microprocessor and also connect read andwrite inputs to corresponding processor controlsignals.

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Connect 16-bit data bus of the memory bank

with that of the microprocessor 8086.

The remaining address lines of BHE and A0

are used for decoding the required chip select

signals for the odd and even memory banks.

The chip select of memory is derived from the

O/P of the decoding circuit.

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Problem: Interface two 4K8 EPROMS and two

4K8 RAM chips with 8086.select suitable

maps.

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Design an interface between 8086 CPU and

two chips of 16K8 EPROM and two chips of

32K8 RAM select the starting address of

EPROM suitably. The RAM address must start

at 00000H.

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