BenchChapter 7: Frames and loops

B52UPHILL

The task

P0 reads a sine wave. On each tick of P2, compare the reading with the one before.

Light the LED on P1 while the wave is rising, and keep it dark while it falls.

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 2 V sine at 25 Hz and V2 2.5 V
Resistors: R1 330 Ω
LEDs: D1 green
Probes: CH1 and CH2

Key idea

XCH swaps A and B, so B can hold the newest reading while A gets the old one.

Hints

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

Hint 1Show

The old reading minus the new one is below 0 when the wave climbs.

Hint 2Show

JL takes the rising case. Anything else must become 0.

Solution

Reveal the Full SolutionThe complete program for UPHILL. 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.

The LED lights while the wave climbs.

u1SC-2 standard

IN P2
IN P0
XCH
SUB B
JL ON
MOV A, 0
ON: OUT P1

CYCLES: 255; at par
ENERGY: 510; at par
NODES: 1; at par
INSTRUCTIONS: 7; at par