A consolidation list. If any of these feels uncertain, return to the relevant section before moving on.
- Convert by hand: decimal 173 to binary; binary 1011 0110 to hex; hex BAD to decimal. No calculator. Time yourself, you should reach 30 seconds per conversion.
- Simplify using a 4-variable K-map. The minimal SOP has 3 product terms.
- Build a 4-bit ripple-carry adder with paper-and-pencil from full adders. Verify by adding 0011 + 0101 step by step, tracking the carry.
- Sketch the carry-lookahead equations for a 4-bit adder in terms of and . Compare gate count to ripple-carry.
- Design an FSM for a single-button "off / on / dim" cycle: pressing the button cycles state. Three states, one input, one output. Assign states (2 bits is enough), write next-state and output tables, derive D flip-flop input equations.
- Simulate a 3-bit Johnson counter in your head: list all 6 states. Then write the same counter in Verilog. Use a free simulator (Icarus, Verilator, or EDA Playground) to check.
- Try Falstad's Circuit Simulator (free, browser-based): build a 2-input NAND, then chain three of them to make a SR latch, set/reset it, and watch the bistability.
- Code a Moore traffic light in Verilog: 3 states (green, yellow, red), with timing inputs from a counter. Synthesize and observe the resource use.
When all of these feel comfortable, you are ready for Chapter 5 on Pulse and Digital Circuits, where we dive into the analog realities of how these digital abstractions actually behave when transistors switch in nanoseconds.