Bidirectional Registers• Either enable or load only active .• During load input lines active output line float• During Enable output lines active input linefloat.• Input and output pins are shorted.• Single set of wires(path) between register andw-bus.
ALU and FlagsALU :- Includes both arithmetic and logicaloperation4 or more control bits for determining theoperation to be performedFlag: Represent the status of the arithmetic andlogical operationFilp flops are used;Zero Flag(Z)Sign Flag(S)
Temp,B,and C registersTemporary register (TEMP)Register B and C are used to move data duringprogram run and accessible to programmers.
Outport Ports2 output ports(3 and 4)Port 3 : Drives Hexadecimal displayPort 4: sends ACKNOWLEDGE signals used tohexadecimal encoder.(Handshaking)Serial Out: Serial Transmission of data.
Microprocessor InstructionLDA and STAEg:LDA 2000HSTA 8000H
Register InstructionADD and SUBEg ADD B /SUB BADD BADD CSUB BSUB C
Register InstructionINR and DCRINR A/DCR AINR B/DCR BINR C/DCR C
Jump And Call InstructionJMPJMP 3000HJM (Jump if Minus)JZ(Jump if zero)JNZ(Jump if not zero)
Jump And Call InstructionCALLSubroutine ????Call is used to call the subroutineRetReturn back from subroutineProgram Counter contents ????-----stored in the last two location of memory(FFFEH and FFFFH)
Logic InstructionCMA-Complement the accumulatorANA-And the accumulator with specified registereg ANA BORA- OR the accumulator with specified registereg ORA BXRA- XOR the accumulator with specified registereg XRA B
ANI: And ImmediateEg ANI C7H (AND accumulator with immediatedata C7H)ORI: OR immediateEg ORI C7HXRI: XOR immediateEg XRI C7H
Other InstructionOUT ( OUT byte eg: OUT 03H: accumulator to designated port)HLTIN(Input : Enter the data from designated input port to accumulator)eg: IN 02HNOPRAL(Rotate the accumulator left)A=1011 0100 After executionA=0110 1001RAR (Rotate the accumulator right)A= 1011 0100After executionA=0101 1010