# 8. GPIO & Hardware Discipline

## Overview
Proper hardware discipline is essential to prevent intermittent failures and ensure that the ESP32-S3 operates within its design limits.

## Mandatory Rules
The following rules must be strictly followed during hardware design and firmware configuration:

1.  **No Strapping Pins:** Avoid using strapping pins (GPIO 0, 3, 45, 46) for general-purpose I/O that could interfere with the boot process.
2.  **I²C Pull-up Audit:** Ensure all shared I²C buses have appropriate physical pull-up resistors. Do not rely solely on internal pull-ups for industrial reliability.
3.  **No ADC2 with Wi-Fi:** The ADC2 unit cannot be used when Wi-Fi is active. All analog sensors must be connected to ADC1 pins.

## Canonical GPIO Map
A single, authoritative GPIO map document must be maintained. This document serves as the "source of truth" for both hardware engineers and firmware developers, preventing pin conflicts and ensuring consistent behavior across hardware revisions.

| Pin | Function | Direction | Notes |
| :--- | :--- | :--- | :--- |
| ... | ... | ... | ... |

By adhering to these disciplines, the project avoids the "maker-grade" shortcuts that often lead to unreliable performance in production environments.
