Practice challenges
Each challenge gives you a spec and a locked testbench — write the module until the bench says PASS. Instant grading in your browser, waveforms when it fails, and your progress is remembered on this device.
Combinational
01 · Wire It Up
Your first combinational expression: three gates, one assign.
02 · Four-Way Mux
Route one of four inputs to the output with a case statement.
03 · 3-to-8 Decoder
One-hot outputs: exactly one line high, chosen by the address.
04 · Rising-Edge Detector
Your first stateful circuit: emit a one-cycle pulse on every 0-to-1.
Sequential
05 · Up/Down Counter
A 4-bit counter with enable and direction — wrap included.
06 · Gray Code Counter
Count in Gray order: every step flips exactly one bit.
07 · Loadable Shift Register
Parallel in, serial out: the heart of every serializer.
08 · Sequence Detector: 110
A state machine that spots a pattern in a serial stream — overlaps too.
Systems
09 · Tiny FIFO
Depth-4 synchronous FIFO with show-ahead read — the real deal.
10 · Mini ALU
Four operations, one zero flag — the capstone in miniature.
New to HDL? The course teaches everything these challenges practice — and the playground is free-form when you just want to experiment.