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Subtractor /Multiplier

Subtractor /Multiplier. Section 4.5 & 4.7. Outline. Delay Four Bit Subtractor Multiplier. Four Bit Adder. Erroneous Results When Delay is inserted in half_adder.v. Four-Bit Adder. C 4 is calculated last because it takes C 0 8 gates to reach C 4 .

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Subtractor /Multiplier

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  1. Subtractor/Multiplier Section 4.5 & 4.7

  2. Outline • Delay • Four Bit Subtractor • Multiplier

  3. Four Bit Adder

  4. Erroneous Results When Delay is inserted in half_adder.v

  5. Four-Bit Adder C4 is calculated last because it takes C0 8 gates to reach C4. Each FA uses 2 XOR, 2 AND and 1 OR gate. A four-bit adder uses 8 XOR, 8 AND and 4 OR gate.

  6. Build a Full-Adder Circuit M1 M2 w1 w2 w3 One gate-delay

  7. Wait for the four bit adder circuit to compute the results

  8. Verilog and Jobs Job: Mixed signal design job in San Jose, CA Level: BS/MS in EE • Job Description: We are seeking a Mixed-Signal ASIC Verification Engineer. The successful candidate will be a key member of the team developing custom ICs for display modules based on the QMT SMI display technology. Hands on technical contributor in verification of Mixed-Signal ASICs and IP development projects. A candidate will help architect, specify, and lead the implementation of mixed Analog/Digital verification projects using high level verification languages. You will work very closely with analog circuit design team, digital design team, and mixed-signal ASIC project leaders to implement complete verification environments and methodologies. Design Mixed-Mode testbenches using SystemVerilog, create VerilogAMS models for analog circuit, create checkers, use ADE/Irun environment to simulate and execute tests in NCSIM/SimVision. Log results and verify with automatic checker. Responsibilities: Create re-usable AMS testbenches from grounds up using advanced verification methodologies (like UVM, OVM etc.) with emphasis towards behavioral modeling of analog blocks, closed-loop simulation with digital design and analog behavioral models and/or transistors by using Cadence Virtuoso schematic editor and ICFB tool environment, and automated & coverage-driven verification. Develop and maintain behavioral models (VerilogA/VerilogAMS) of analog and mixed-signal blocks including data converters(ADC/DAC), power converters (charge pump, buck converter, boost converter), switch mode power supplies, LDOs, analog switches/muxes, PLLs, level-shifters, amplifiers, thermal sensors.

  9. Verilog and FPGA Parker Aerospace, an operating segment of Parker Hannifin Corporation, is one of the world’s leading producers of flight control, hydraulic, fuel, inerting, fluid conveyance, thermal management, and engine systems and components for the aerospace industry. We design and build equipment for virtually every aircraft and aero engine being produced in the world today. ENGINEER III – AIRCRAFT ELECTRONICS SUMMARY Responsible for design, verification and certification of FPGA based aerospace firmware. Requirements creation and validation, conceptual design, detail design and testing. Create control circuits, design (writing of VHDL), develop timing constraints, simulate (functional and timing), place and route synthesized designs. Ensure all required data items and artifacts to support FAA SIO audits are correct and complete. Creation of verification requirements based test cases and oversight of verification simulations by supplier. Verify test cases, procedures, and test benches are created to satisfy existing design requirements. Perform independent audit of verification artifacts. Participate in peer design reviews and support continuous process improvements. Bachelor’s Degree in Electrical Engineering or related engineering discipline with preferably six plus years of experience in the design, development and certification of aerospace firmware. A Master’s Degree is a plus. Specific experience in DO-254 certification required. Specific experience in motor drive and flight control applications is a plus. Experience with ARINC-429, CAN, SPI or other serial interfaces. Experience in requirements capture and validation. Experience with VHDL design and verification. Experience with Xilinx and Altera development tools. Experience with ModelSim/QuestaSim to perform simulation and debug of VHDL design. Experience with in-circuit verification techniques. Possess excellent trouble shooting skills and knowledgeable in Chipscope / Signal Tap FGPA debugging tools. Experience creating requirements based test cases. Experience creating simulation / verification test bench using VHDL / Verilog language. Experience in supporting FAA SOI audits. Leadership experience a plus. Strong technical writing, verbal and written communication skills. Excellent work ethic. Able to work well in teams (local as well as remote) and is self-motivated.

  10. Verilog and Local Jobs

  11. Subtraction

  12. Unsigned Number (2-bit example)

  13. Unsigned Addition • 1+2=

  14. Unsigned Addition • 1+3= (Indicates Overflow) (Carry Out) Overflow can be an issue in unsigned addition.

  15. Unsigned Subtraction (1) • 1-2= (1’s complement) (2’s complement)

  16. Unsigned Subtraction (2) • 2-1= Discarded

  17. Summary for Unsigned Addition/Subtraction • Overflow can be an issue in unsigned addition (An overflow is detected from the end carry out of the most significant position) • Unsigned Subtraction (M-N) • If M≥N, and end carry will be produced. The end carry is discarded. • If M<N, • Take the 2’s complement of the sum • Place a negative sign in front

  18. Four-Bit Adder-Subtractor For detecting overflow in unsigned numbers For detecting overflow in addition/subtraction of signed numbers

  19. The Mode Input (1) If M=0, = If M=1, = B0

  20. The Mode Input (2) If M=0, If M=1,

  21. M=0 (Addition) B3 B2 B0 B1 0

  22. M=1 (Subtraction) 1 2’s complement is generated of B is generated!

  23. Four-Bit Adder-Subtractor X2 X0 X3 X1 X_FA_2 X_FA_1 X_FA_0 X_FA_3 FA3 FA2 FA0 FA1 X4

  24. Verilog Model of a 4 bit adder/subtractor

  25. Sample output of adder/subtractor circuit Ignore V if you are working with unsigned numbers.

  26. Binary Multiplication

  27. Two-Bit Binary Multiplier (multiplicand) (multiplier)

  28. Use an AND gate to multiply A0 and B0

  29. Hardware Correlation

  30. Hardware Correlation G1 G0 G3 G2 W2 W0 W1 W3 HA1 HA0

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