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EEE 4211 Microprocessor and I/O System SAP-1. SAP-1 Timing Cycle for LDA Routine LDAT1T2T3T4T5T6 Cp010000 Ep100000 Lm'011011 CE'110101 Li'110111 Ei'111011.

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Presentation on theme: "EEE 4211 Microprocessor and I/O System SAP-1. SAP-1 Timing Cycle for LDA Routine LDAT1T2T3T4T5T6 Cp010000 Ep100000 Lm'011011 CE'110101 Li'110111 Ei'111011."— Presentation transcript:

1 EEE 4211 Microprocessor and I/O System SAP-1

2

3 SAP-1 Timing Cycle for LDA Routine LDAT1T2T3T4T5T6 Cp Ep Lm' CE' Li' Ei' La' Ea Su Eu Lb' Lo' InstructionT1T2T3T4T5T6 LDAEp Lm’CpCe’ Li’Ei’ Lm’Ce’ La’X

4 SAP-1 control Signals Instruction T1T2T3T4T5T6 LDA Ep Lm’CpCe’ Li’Ei’ Lm’Ce’ La’X ADD Ep Lm’CpCe’ Li’Ei’ Lm’Ce’ Lb’Eu La’ SUB Ep Lm’CpCe’ Li’Ei’ Lm’Ce’ Lb’Su La’ OUT Ep Lm’CpCe’ Li’Ea Lo’XX HLT Ep Lm’CpCe’ Li’ XXX

5 State Equations Ep= T1 Cp= T2 Lm’= T1+ T4.LDA+T4.ADD+T4.SUB Ce’= T3+ T5.LDA+T5.ADD+T5.SUB Li’= T3 Ei’= T4.LDA+T4.ADD+T4.SUB La’= T5.LDA+T6.ADD+T6.SUB Ea= T4.OUT Su= T6.SUB Eu= T6.ADD Lb’= T5.ADD+T5.SUB Lo’= T4.OUT

6 Microprogramming Reduces the complexity of control circuit. In Microprogramming, microinstructions are stored in a ROM instead of producing them with hardwired control matrix.

7 Construction of Microinstruction for SAP-1 For LDA, at t1, the states of control Signals are: Cp=0 Ep=1 Lm=1 Ce=0 Li=0 Ei=0 La=0 Ea=0 Su=0 Eu=0 Lb=0 Lo=0 So the Controller has to generate the control word/ Microinstruction or 600h In this way, microinstructions will be generated and stored in the control ROM.

8 SAP-1 Control ROM AddressCONRoutineActive 0H5E3H Fetch Ep,Lm' 1HBE3HCp 2H263HCE',Li' 3H1A3H LDA Lm',EI' 4H2C3HCE',La' 5H3E3HNone 6H1A3H ADD Lm',EI' 7H2E1HCE',Lb' 8H3C7HLa',Eu 9H1A3H SUB Lm',EI' AH2E1HCE',Lb' BH3CFHLa',Su,Eu CH3F2H OUT Ea,Lo' DH3E3HNone EH3E3HNone FHXXNOT USED

9 SAP-1 Address ROM AddressContentsRoutine LDA ADD SUB 0011XXXXNONE 0100XXXXNONE 0101XXXXNONE 0110XXXXNONE 0111XXXXNONE 1000XXXXNONE 1001XXXXNONE 1010XXXXNONE 1011XXXXNONE 1100XXXXNONE 1101XXXXNONE OUT 1111XXXXNONE

10 Microprogrammed Controller circuit I7 I6 I5 I4 Address ROM 16X4 Presettable Counter Control ROM T3 Load CLR T1 CLR 12 bit CLOCK

11 Implementation of HLT Instruction Decoder 4-16 I7 I6 I5 i4 LDA ADD SUB OUT HLT Oscillator/ Clock Generator CLK

12 What is the motivation behind Microprogramming? With complete block diagram briefly explain the controller/sequencer design using microprogramming technique. Control word of the controller/sequencer is given. Specify SAP-1 Control ROM and Address ROM contents.


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