Question

Which priority encoder is used in MC68000?

(a) 4-to-2 priority encoder

(b) LS148 7-to-3

(c) 2-to-4 priority encoder

(d) LS148 3-to-7

The question was asked in examination.

My question is taken from The mechanism of Interrupts topic in portion Interrupts and Exceptions of Embedded Systems

Answer 1

Right choice is (b) LS148 7-to-3

Explanation: The LS148 7-to-3 priority encoder is used in MC68000. This converts the seven external pins into a three-bit binary code.