Combinational Logic Design

Transistor Circuits

• Read Section AND, OR, & NOT Gates of [1, p57-60] , implement the circuit of Fig. 1 with Logisim following the steps descrived in Clip 1.

Activities

1. Implement the circuit of Fig. 2.14 of [1, p59]

2. Implement the circuit of Fig. 2.15 of [1, p59]

3. Implement the circuit of Fig. 2.20 of [1, p62]

4. Implement a circuit of a half adder using CMOS transistors (you can use transmission gates as shown in slide 10 of TGlecture) 

5. Implement a circuit of a 4 to 1 MUX using CMOS transistor  (you can use transmission gates as shown in slide 11 of TGlecture)

Combinational Logic Design Process

Binary number to seven-segment display converter

• Read Example 2.23 of [1, p81-3] and implement the circuit of Table 2.4 following steps of Clip 3. using Logisim

• Create a subcircuit named 'bin2disp7'

• Connect the subcircuit outputs to a seven-segment display and evaluate the circuit operation. 

12-button keypad to 4-bit code converter

• Implement the circuit of a 12-buttom keypad as shown in Fig. 2.42  (with 12 buttons  and 7 outputs) using Logisim;

• Read Example 2.26 of [1, p86-7] and implement the circuit of Table 2.7 following steps of Clip 4. using Logisim;

• Create a subcircuit named 'key2bin'

• Connect the subcircuit inputs to 12-buttom keypad and evaluate the circuit operation. 

Binary-to-BCD Converter

• Read the four steps of Shift and Add-3 algorithm of the following website (link);

• Recalling Clip 3. Converting a truth table to a combinational circuit with Logisim, implement a circuit from Truth table for Add-3 Module of the following website (link);

• Create the subcircuit 'Add-3';

• Implement the circuit of Fig. 2; conect the uotputs to two seven-segment displays and evaluate its operation

Activities

1. Circuit with 12-button keypad and seven-segment displays

• Using  three seven-segment displays and  a 12-button keypad with keys '0', '1', '2',  '3', '4', '5', '6', '7', '8', '9' ,'+' and 'C'; 

• Considering only one-digit inputs (one key);

• Assuming the button '+' for sum operation and the button 'C' clear the value of displays (putting zero value in all displays); 

• Using Logisim, implement a circuit that shows the cumulative sum (in BCD) of one-digit numbers.

Multiplexed automobile above-mirror display

• Read Example 2.33 of [1, p98-9];

• Fig. 3 shows a block diagram adapted from Fig. 2.59 of [1, p99];

Activities

1. Implementation of  the Circuit for Above-mirror display using an 8-bit 4x1 mux

• Use four 8-bit sliders for inputs T, M, I e Q;

• Use a button for selecting the information to be visualized;

• Connect the button to a 2-bit counter;

• Use four LEDs for indicating which information is being visualized;

• seve-segments displays show information in BCD code; and

• Evaluate the circuit operation.

Automating Two-Level Logic Size Optimization

Read Section Automating Two-Level Logic Size Optimization of [1, p325-8], and review the steps of Slide 1.

Activities

1. Solve Exercises 6.7-6.11 e 6.15 of [1, p389]

2. Perform  two-level logic optimization of  F(x,y,z) = x'yz' +x'y'z + x'yz + xy'z + xyz' + xyz using a K-map and Automating Two-Level Logic Size Optimization

Bibliography and Resources

Bibliography

[1] Vahid, Frank; Sistemas digitais: projeto, otimização e HDLs 

• Library ID: 621.382:004 V127s

• Digital library: 9788577802371 

External Online Resources

• Frank Vahid Publications