In this experiment you will demonstrate the operation of a decoder-driver circuit that accepts a binary or BCD input code and generates the 7 segment display signals to produce the numbers 0 through 9 and other characters.
- Microprocessor power supply
- Wire the latch circuit shown in fiqure 2. The Set (A) and Reset (B) are the inputs and C (L1) and C (L2) are the outputs.
- Apply power to the circuit and create a truth table for S and R Inputs and C and C outputs.
- Wire the latch circuit shown in figure 3. Repeat steps 1. and 2. for circuit 3. These new outputs are labeled D and D. Why do we call this circuit a basic memory unit? What happens to the outputs when S and R both 0? Refer to the textbook (Katz) for a discussion of flip-flops (chapter 6).
- Construct the circuit shown in figure 4. Use the TTL handbook to verify the correct conections. The pin connections for the 74LS48 and the 7-Segment Display are shown in fiqure 5.
- Calculate the value of the resistor between the 74LS48 and the 7-seg LED.
- Apply power to the circuit. Create a truth table for figure 4. Do the LEDs L1-L4 which output the binary word agree with the output of the 7-Segment LED? What does the 7-Segment LED read in binary states 1010-1111? What do you think the LT, RBI and BI/ RBO pins do?