Traffic Light 02b — Green then yellow

Briefing

Now a timer changes the light, not a switch. The light rests on red. A GO pulse turns it green; after 3 seconds green ends and yellow begins. RESET_PB puts it back to red. Only one lamp is lit at a time. Red shows whenever neither green nor yellow is on.

Objectives

• Idle: red on, green and yellow off
• GO: green on, red off
• After 3 seconds: green off, yellow on, red still off
• RESET_PB: back to red

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1Idle → red only

   With nothing pressed, only the red lamp is on

2. #2GO → green on, red off

   GO starts the green phase

3. #3After 2.5 s → still green

   Green holds for its full 3 seconds

4. #4After 3.4 s → yellow on, green and red off

   The timer ends green and starts yellow

5. #5RESET → red again

   RESET_PB returns the light to red

6. #6After a reset, GO runs a full green phase again

   A second cycle: green holds 2.5 s then turns yellow