Lab Description:

In this lab you will creating a $4-$bit Arithmetic and Logic Unit $($ALU$).$ This is the heart of a microprocessor and the circuit can start to get very complicated. Take your time, be careful with your connections and busses and test, test, test! As always, the lab manual does an excellent job explaining what you need to know. The lab starts on page $88$ of your Lab Manual.

In addition to the normal LogicWorks files you will be turning in $($listed at the bottom$),$ you are also to turn in a file which lists the functions of your ALU. Specifically, fill in the following table. I have provided the possible answers afterwards. You can do this by tracing the logic in your circuit, or by testing. The file can be Word, Excel, Text, PDF or anything else I can read.

You are filling in the last column of the following table with the answers that are listed BELOW this table.

Example: The first row is asking what function do you get when ~A$\_$Only is LOW, Logic$/$~Arith is LOW and ~Invert is LOW? Put another way, what function takes only an A$,$ is an Arithmetic operation $($not a logical one$)$ and A is somehow inverted? Of the $8$ possible answers, only $4$ of them include ONLY an A $($no B$)$: $-$A$,$ A$,$ A$,$ NOT A$.$ Which of these $4$ is an arithmetic operation $($not a LOGICAL operation$)$ and involves an inverse? My guess is $-$A$.$ It involved arithmetic and an inverse. Now you do the other $7$ rows.

$/$~A$\_$Only Logic$/$~Arith $/$~Invert Function

$000?$

$001?$

$010?$

$011?$

$100?$

$101?$

$110?$

$111?$

Possible Functions:

$-$A$,($NOT A$)$ OR B$,$ A $($you can use this answer twice$),$ A $+$ B$,$ A OR B$,$ B $-$ A$,$ NOT A

Hint: You are to fill in the last column of the table with the answers that are listed ABOVE. For example, the first row is asking, what function do you get when ~A$\_$Only is LOW, Logic$/$~Arith is LOW and ~Invert is LOW? Put another way, what function takes only an A$,$ is an Arithmetic operation and A is somehow inverted? Of the $8$ possible answers, only $4$ of them include ONLY an A $($no B$)$: $-$A$,$ A$,$ A$,$ NOT A$.$ Which of these $4$ is an arithmetic operation $($not a LOGICAL operation$)$ and involves an inverse? My guess is $-$A$.$ It involved arithmetic and an inverse. Now you do the other $7.$

Notes:

The lab manual talks about writing a lab report. We will not be doing this. Your circuits will speak to your success on this project.

The manual includes a "Lab Report Grade Sheet" and "Self$-$Assessment Worksheet". These are not needed.

Make sure the file names and components match the required names exactly: Spelling, Upper$/$Lowercase$,$ Underscores.

Reminder: The best demos will have labeled binary switches or hex keypads on the left side, the circuit or components in the middle and labeled binary probes or hex displays on the right.

If you are interested, check out the spec for $74181$Links to an external site.. You cannot use this for your project $($even though it is in one of the libraries$).$

Your design must use Hex keypads and Hex displays when a $4-$bit number is being used. For example:

AddOr.png

Required Activities:

Read through the Lab and perform each of the activities.

What to Submit:

Circuit Files

Add$\_$or$\_$demo

ALU$\_$demo

Not$\_$neg$\_$demo

Library Components $($in flast.clf$)$

ADD$/$OR

ALU

NOT$/$NEG

Other

Function Table $($as described above$)$

Testing:

Here is some sample data you can use for testing your circuit.

Add$/$Or

Input:

A $=5$

B $=6$

Output:

Add $=$ B

Add $+$ Cin $=$ C

OR $=7$

Pass Through $=5$

Not$/$Neg

Input:

A $=5$

Output:

Not $=$ A

Neg $=$ B

Pass Through $=5$

ALU

Input:

A $=5$

B $=3$

Cin $=0$

Output:

Logic$/$~Arith

$/$~Inv

$/$~A$\_$Only

Result

$0$

$0$

$0$

B

$0$

$0$

$1$

E

$0$

$1$

$0$

$5$

$0$

$1$

$1$

$8$

$1$

$0$

$0$

A

$1$

$0$

$1$

B

$1$

$1$

$0$

$5$

$1$

$1$

$1$

$7$

Rubric$\backslash$table$[[$Logic$/$ Arith,$/$ Inv,$/$ A$\_$Only,Result$],[0,0,0,$B$],[0,0,1,$E$],[0,1,0,5],[0,1,1,8],[1,0,0,$A$],[1,1,0,5],[1,1,1,7]]$

It would almost be nice if you could make a video so I could follow along I$\text{'}$m really struggling with this