80386 MICROPROCESSOR

• Introduction• 80386

• 80386DX• 80386SX• 80386EX• Pin Outs

• The Memory System

INTRODUCTION32 bit versionFeatures:

Multi taskingMemory management

Virtual memorySoftware protection

Large memory system (4 GB)

What is 80386????????

80386 is,Very popular in embedded applicationsOutput current available is 8 mAPower supply current required is 320 mA when operated in 33 MHz

80386Single +5 V power supply

Current Frequency

550mA 25 MHz

500 mA 20 MHz

450 mA 16 MHz

600 mA 33 MHz

80386DXPackaged in a 132-pin grid arrayAddresses 4 GB of memory32 bit data bus32 bit address busOutput pin current 4 mAInput pin current +10 or -10 micro Ampere

80386sxReduced bus version of 80386 where 32 bit is not neededUsed in personal computersPopular and less costly versionUsed in Windows 3.11Available with power supply +3.3 V

80386 EX

o AT bus system, odynamic RAM controller, oProgrammable chip selection logic,o26 address pinso16 data pinso24 I/O Pins

BANK ENABLE (BE0-BE3):To select the access of a byte, word, or double word of data.ADDRESS DATA STROBE (ADS):Active when 80386 has got a valid memory address.CLOCK TIMES 2 (CLK2):Driven by a clock signal that is twice the operating frequency

LOCK:Used when DMA access is used.D/C:Logic 1: data bus contains dataLogic 0: executes interrupt acknowledgeBS16:Chooses the bus size

NA:Outputs the address of the next addressBUSY:Used by the WAIT instruction.ERROR:Error is detected by the co-processor.NMI:Non Maskable Interrupt.

MEMORY SYSTEM

BUFFERED SYSTEM:Connected to buffersTo increase fan-out from its address, data, control connections.25 MHz using 50 MHz clock signal (Oscillator modules)HLDA-enable the buffered system

CACHEHigh speed memory systemImproves overall performance of the memory systemsAccess times<<10 nsSize of the cache memory depends on the application of the processor

If a program is LARGE, Largest cache size is recommendedIf small, small size is enough

CACHE

LEVEL 1 LEVEL 2Internal cache size:32k- 1M byte

INTERLEAVED MEMORY SYSTEMS

High costMemory access time can be lengthened without the need for wait statesEmploys 2 complete buses called 2 way interleave4 complete buses- 4 way interleave

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