Lab project - ECE 421L 

Authored by Worku, Yetneberk

Email: workuy@unlv.nevada.edu

NHSE ID 1007208058

11/10/2014

introduction:

The purpose of this project is to make 8-bit Arithmetic Logic Unit (ALU), that will implement on cedence; there are different ways to design of the ALU, however on this project we have the most logic gate schematice privous lab. so, this project the arithmetic and logic unit (ALU) is a combinational citcuit that performs logic and aritmatic operations; the operations performed by an ALU are controlled by a set of function-select inputs and depending on the value of the control lines, the output will be addition, subtraction, AND, and OR  of the inputs. 

F(1) and F(0) as the controls for deciding which function to perform see the following table

fig_table_f1_and_f0.JPG

to perform substractor A-B will it takes the two's compliment of B that perform this [A+(-B)], and B useing 1 for the carry-in. for adding use A+B.

The ALU symbol, i use see the image below.
fig_ALU_symbol.JPG
the schematically, here is what i want to bulid, see the image below.

fig_ALU_schematic.JPG

Next, need to check the alu perform the right output, that is done by doing  some simulations. i will start with addition A+B simulations, which is my input F0=1, and F1=0. for instance if value of A is 11000010, and  the value of B is 01110011. the result i am expecting is 00110101. see the schematic and the simulations reslt below.
ADD_SCH.png
ADD_INPUT.png

ADD_OUTPUT.png

Next, substraction operations [A+(-B)] simulations, which is my input F0=1, and F1=1. for instance if value of A input is 11100010, and  the value of B input is 01000001, then complement of B is 10111110. the result i am expecting is 10100001. see the schematic and the simulations reslt below.
SUB_SCH.png

SUB_INPUT.png
http://cmosedu.com/jbaker/courses/ee421L/f14/students/workuy/lab7/lab7.zipSUB_OUTPUT.png
Next, logic operatins AND simulations, which is my input F0=0, and F1=0. for instance if value of A input is 11100010, and  the value of B input is 01000001. then according to the truth table; the result i am expecting is 01000000. see the schematic and the simulations reslt below.
AND_SCH.png
AND_INPUT.png
AND_OUTPUT.png
Next, logic operatins OR simulations, which is my input F0=1, and F1=1. for instance if value of A is 11100010, and  the value of B is 01000001. then according to the truth table; the result i am expecting is 11100011. see the schematic and the simulations reslt below.
OR_SCH.png
OR_INPUT.png
http://cmosedu.com/jbaker/courses/ee421L/f14/students/workuy/lab7/lab7.zipOR_OUTPUT.png
concludes, for the first part of  project is both the or and and operatins cout still output a value carry out shoud be ignored

Part Two (II) project

On this part, we need to create a layout for 8 bit ALU. however,  to accomplish this task need to create one bit ALU then connect each other up to 8 bit. for one bit ALU see below the schematic, extracted and layout, also see the result for DRC and LVS.
fig_one_bit_alu.JPGfig_one_bit_alu_schematic.JPGfig_one_bit_alu_layout.JPGfig_one_bit_alu_lvs_pass.JPG
next, using one bit alu, then can bulid the 8 bit alu. see below the schematic, extracted and layout, also see the result of DRC and LVS.
fig_8_bit_alu_scematic.JPGfig_8_bit_alu_layout.JPGfig_8_bit_alu_passing_lvs_halla_luya.JPG
finally, this is the end of ALU.....
backup work see below
fig_backup_project.JPG

the project download is here

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