PLATFORMS - Reading data from memory

by **Admin** Wed Mar 11, 2015 11:05 am

Reading data from memory (Also known as loading data)

Step One: Set the address (of the memory location) on the address bus.

Step Two: Set the read/write wire of the control bus high. ß {I.e. Request a read operation}

Step Three: Set the address valid control wire high.

Step Four: The address valid signal, together with the value on the address bus will activate the chip select wire on the appropriate memory chip.

Step Five: The contents of the memory location will now be placed on the data bus.

Step Six: Read the value from the data bus (usually into a register in the microprocessor)

Step Seven: The read/write address valid and chip select wires can now all be set low.

Breakdown of the operation:

1-      The address goes on the address bus

2-      Read/write wire set high

3-      Address valid control wire set high

4-      Address valid signal + value on address bus activates the chip select wire

5-      Contents put on the data bus from memory location

6-      Value from data bus read to register

7-      The wires previously set to high can now be set to low

Things to remember:
-          The read/write wire is usually labelled “R/W”

-          Address Bus: Determines the location in memory that the data will be read from or written to.

-          Data Bus: Contains the contents that have been read from memory or waiting to be written to memory.

-          Control Bus: Manages the information flow between components and ensures the operation happens at the right time.

PLATFORMS - Reading data from memory

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PLATFORMS - Reading data from memory