Question

Answer 1

Answer 2

The input combinations are representing the numbers 0 through 9 should be displayed as decimal digits. The input combinations 0000, 0001, and 0010 should be interpreted as an error, and an “E” should be displayed in the seven segment indicator.

Assume that, the input combinations 1101, 1110, and 1111 are never occurs. So, these combinations are represented as don’t cares.

Refer to Figure 8-15 for a circuit driving seven-segment module in the text book.

Draw the truth table for excess-3 code converter to drive a seven-segment indicator.

From Table 1, the maxterm expansions of seven-segment indicator are as follows:

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 1, the minimized POS expression for is,

The NOR gate representaion of expression is,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 2, the minimized POS expression for is,

The NOR gate representaion of expressionis,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 3, the minimized POS expression for is,

The NOR gate representaion of expressionis,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 4, the minimized POS expression for is,

The NOR gate representaion of expression is,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 5, the minimized POS expression for is,

The NOR gate representaion of expressions is,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 6, the minimized POS expression for is,

The NOR gate representaion of expressions is,

Derive the minimized product-of-sums expression for using Karnaugh map.

From Figure 7, the minimized POS expression for is,

The NOR gate representaion of expression is,

The minimized POS expressions for seven segemnt indicator are as follows:

The common terms in the above seven segemnt indicator expressions are,

Design the required logic circuit using two, three and four-input gates and inverters.

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From the given data, the maximum allowed gates are 18-NOR gates.

In Figure 8, 18-NOR gates are used.

Thus, the Exces-3 code converter to drive a seven-segment indicator is designed using only two, three, and four-input NOR gates and inverters.