(Regular Logic Implementation Methods) We wish to extend the BCD-to-seven-segment LED display decoder to become a hexadecimal LED display decoder. The LED representations of the hex digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 are exactly the same as for the equivalent BCD digits. Figure Ex. 4.28 shows how the segment displays should be illuminated to denote the hex digits A (1010), B (1011), C (1100), D (1101), E(1110), and F (1111).
(a) Obtain the minimized sum-of-products implementations for the display inputs.
(b) Show how to implement the logic for the extended design as a PLA with four inputs and seven outputs. Draw the AND array and OR array, and indicate which connections must be made to implement the function. For each output from the AND array, indicate along the wire the product term it is implementing.