BenchChapter 6: Trees

B40STEPPER

The task

V1 sends a clock to P0. On each rising edge, raise the duty on P1 by 25 percent.

After 100 percent, the next edge brings it back to 0.

The board

The chip's ports, each with its kind and the parts its signal reaches. Cyan reads, lemon writes. On a narrow screen, scroll the board sideways to see all of it.

Sources: V1 5 V square at 125 Hz
Resistors: R1 1 kΩ
Capacitors: C1 1 µF
Probes: CH1 and CH2

Key idea

Wait for P0 to fall, then for it to rise. That is one edge.

Hints

Each hint goes a step further than the one before. Open them one at a time.

Hint 1Show

B keeps the duty from edge to edge.

Hint 2Show

ADD 25 and MOD 125 count 0, 25, 50, 75, 100, and around again.

Solution

Reveal the Full SolutionThe complete program for STEPPER. Open it only when you want the answer.

The reference program

The game's own solution. It passes every test and scores exactly par on every benchmark.

Each rising edge of the clock climbs a quarter.

u1SC-2 standard

L: IN P0
JNZ L
H: IN P0
JZ H
MOV A, B
ADD 25
MOD 125
MOV B, A
OUT P1

CYCLES: 800; at par
ENERGY: 1600; at par
NODES: 1; at par
INSTRUCTIONS: 9; at par