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Arduino Mega 2560 chipplet: Server error 7: Pin not found for analog pins A0–A15 #47

Description

@shiwanghua

Title: Arduino Mega 2560 chipplet: Server error 7: Pin not found for analog pins A0–A15

Description:

Summary

The Arduino Mega 2560 chipplet rejects analog pin labels A0 through A15 with Server error 7: Pin not found, despite these being valid physical pins on the real ATmega2560 (A0–A15 map to digital pins 54–69).

This was working previously — simulations using diagrams with mega:A3, mega:A1, etc. ran successfully, then after a Wokwi service disconnect/reconnect, all subsequent simulation attempts on diagrams referencing analog pins fail with this error.

Steps to Reproduce

  1. Create a diagram with an Arduino Mega 2560 and wire any component to an analog pin, e.g.:
    connections: [["pot1:SIG", "mega:A3", "black"]]
    
  2. Upload firmware and start simulation
  3. Observe error: WokwiError: Server error 7: Pin not found: A1 (or A0, A2, A3, etc.)

Expected Behavior

Analog pin labels A0A15 should be accepted as valid pin identifiers for the Arduino Mega 2560 chipplet, matching real hardware behavior.

Actual Behavior

All analog pin labels (A0A15) are rejected with Server error 7: Pin not found. Digital pin labels (e.g., mega:2, mega:13) work fine.

Environment

  • Wokwi API (free tier), via wokwi_client Python library
  • Arduino Mega 2560 chipplet (wokwi-arduino-mega)
  • Firmware compiled with PlatformIO, board = megaatmega2560

Impact

This blocks ~85/126 (~67%) of our embedded LLM evaluation benchmark (EmbedBench) test cases, since the golden diagrams reference analog pins extensively for potentiometers, sensors, and other components.

Additional Context

  • The error first appeared after a disconnect/reconnect cycle. Simulations that were already running before the disconnect completed successfully with the same diagrams (including those using A0–A5). After reconnecting to Wokwi, all new simulation attempts with analog pins fail.
  • This strongly suggests a recent chipplet version change that dropped analog pin alias support.
  • Real Arduino Mega 2560 hardware maps A0–A15 to digital pins 54–69, and these pin labels are standard in the Arduino ecosystem.

Activity

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