UPC EETAC Bachelor's Degree in Telecommunications Systems and in Network Engineering EEL

L1.3

Lecture 4

L1.4: Designing combinational circuits

P1 design plan A: canonical circuits, minimisation (minilog), circuits using SoP, PoS

L1.5

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1.5. Design flow for inventing combinational circuits using VHDL

1.5.1. Specifications, design concept map (our complete list of design plans)

1.5.1.1. Symbol or entity

1.5.1.2. Truth table

1.5.1.3. Example timing diagram

1.5.2. CSD design plans

1.5.2.1. Plan A: structural/equations single-file

1.5.2.1.1. Canonical equations: sum of minterms or product of maxterms. 

Wikipedia entry for canonical forms.

For example, we can invent four circuits from Circuit_W truth table:

Circuit_W plans

Specifications: Invent Circuit_W1 from the truth table of Circuit_W using the canonical expression product of maxterms.

Specs

Plan and development:

Location for this project files, for instance: pictures, scanned files, report, etc.

C:\CSD\P1\Circuit_W\Circuit_W1\

plan and develoment

Test: if you test the circuit for example using WolframAlpha or Proteus you will place in this project folder your computer files such as "equations.txt" or "Circuit_W3.pdsprj".

Specifications: Invent Circuit_W2 from the truth table of Circuit_W using the canonical expression sum of minterms.

Circuit_W2

Plan and development:

Location for this project files, for instance: pictures, scanned files, report, etc.

C:\CSD\P1\Circuit_W\Circuit_W2\

development

Test: if you test the circuit for example using WolframAlpha or Proteus you will place in this project folder your computer files such as "equations.txt" or "Circuit_W3.pdsprj". However:

testing

1.5.2.1.2. Minimised equations: SoP or PoS

- Espresso heuristic algorithm: minilog.exe (we use Notepad++ as enriched text editor for writing text tables).

- Truth table translated to Minilog text input format (.tbl)

- Minilog minimisation results: SoP or PoS logic equations and equation converter

For example:

Specifications: Invent Circuit_W3 from the truth table of Circuit_W using minimised SoP

Plan: this is the procedure to obtain results and complete the project:

1. Circuit_W3 project location:

 C:\CSD\P1\Circuit_W\Circuit_W3\(files)

2. Find and modify a similar tbl file, fr example you can use the file Circuit_P.tbl in minilog tutorial and rename and adapt it to: Circuit_W.tbl

3. Run Minilog and simplify using single output mode (SoM), equation output format, and choose SoP.

4. Equation format that has to be reprocessed by equation_converter.exe so that you get SoP equation with the project entity names for inputs and outputs.

5. Draw the circuit.

6. Check the circuit's equation using WolframAlpha or Proteus.

Development:

- Minilog file describing the truth table: Circuit_W.tbl

Circuit_W3

Test: This means verifying that the circuit that you have designed has the given initial truth table. For instance, this is the Proteus capture: Circuit_W3.pdsprj.

Testing

 

Exercise: Specifications: Invent Circuit_W4 from the truth table of Circuit_W using minimised PoS

Plan: the same as for Circuit_W3 above.

- Circuit_W4 project location: C:\CSD\P1\Circuit_W\Circuit_W4\(files)

 - Run Minilog and simplify using single output mode (SoM), equation output format, and choose PoS. 

Development. Draw the logic circuit

Test: Use Proteus to check the truth table of this circuit or compare your results with your team mates.