Digital Electronics and Logic Design
Digital Electronics and Logic Design tests Boolean minimization, combinational and sequential blocks, timing, and CMOS implementation. Expect K-maps, flip-flop behavior, FSM design, and setup/hold analysis.
Core rules
- Use Boolean identities and K-maps; group 1s in powers of two, including wraparound and don't-cares.
- A D flip-flop samples D at the active clock edge; setup and hold windows must be met.
- Synchronous design uses one clock; asynchronous inputs need synchronization to avoid metastability.
- CMOS static power is low; dynamic power scales as CV²f.
- Mealy outputs depend on state and input; Moore outputs depend only on state.
Worked example
Simplify F(A,B,C)=Σm(1,3,5,7). Write minterms: 001, 011, 101, 111. In every term C=1, while A and B vary. A K-map grouping four cells in the C=1 column gives F=C. If a don't-care at 000 were included, confirm it does not create a larger valid group that changes the required behavior.
Traps
Grouping three cells; using don't-cares as required 1s; mixing active-low and active-high reset; forgetting clock-to-Q delay in timing paths; and treating asynchronous reset release as safe without synchronization.