Basics · 01 of 69
A line, a threshold, a bit
A wire carries a voltage, not a 0 or a 1. A receiver compares it with a threshold: above is 1, below is 0. Edges take time, so when a bit changes depends on how fast the line can move.
- τ = R·C
- 1 µs
- Rise 30–70 %
- 847 ns
- 1 appears after release
- 693 ns
What to look for1 of 31 call · no errors
Turn on the analog view: the line is a voltage that rises along a curve, not a vertical jump.
The digital trace flips where the curve crosses VDD/2, the threshold this lab uses (a real input switches somewhere between V_IL and V_IH). Anything else about its shape is lost.
Double the capacitance and the curve takes twice as long: every 1 now arrives later, though the program didn't change.
Try
Trace
Zephyr callsWhat the program called, and what came back