VL11 · Sem 4 · Digital design
Up/down counter
Aim: Count up or down under control of an input.
🧪 Live simulation🧊 Real-time 3D bench⚠ Simulated values, not physical measurements
🔬 Virtual lab
Starting the lab…
📘 Theory
A direction input selects between adding and subtracting one. Used for position encoders and volume controls.
q⁺ = up ? q + 1 : q − 1
🧰 Apparatus (virtual)
- Yosys
- simulator
📝 Procedure
🎤 Viva questions
How does a quadrature encoder decide direction
From which of two signals changes first.
What happens below zero in 4 bits
It wraps to 15.
🛡️ Safety
Software only. Area and timing use generic teaching assumptions; they are not silicon measurements or sign-off results.