SME
Digital Logic Design
Combinational logic
Use this for “Simplify f(A, B, C) = Σm(0, 2, 5, 7) with a K-map.”
Explore
Cells 0 and 2 touch across the map’s edge, and cells 5 and 7 touch inside it: two pairs give f = A′C′ + AC.
Assumptions
•
Group the 1s in blocks of 1, 2, 4 or 8, as large as you can; each block is one product term.
•
The map lists rows and columns in Gray order (00, 01, 11, 10), so neighbouring cells differ in one input.
•
A don’t-care (X) joins a block only when it makes the block larger.
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
More problem types
Select lines, decoder outputs and truth tables
Use this for “How many select lines does an 8-to-1 mux need? How many rows and functions do 3 inputs give?”
Ripple-carry adder delay
Use this for “A 32-bit ripple-carry adder has 0.5 ns of carry delay per bit. How long does an add take, and how fast can it run?”
Name the gate from its truth table
Use this for “A two-input gate outputs 0 1 1 0 for AB = 00, 01, 10, 11. Which gate is it?”