87c0272687
Research complete from 2026-05-04 session: - M5Stack ESP32 GPIO pinout reference (PLAY) - Gear ratio selection guide for FRC mechanisms (2890) - MegaTag vision localization concept (2890/PhotonVision)
103 lines
3.2 KiB
Markdown
103 lines
3.2 KiB
Markdown
---
|
|
title: "M5Stack Core ESP32 GPIO Pinout Reference"
|
|
tags:
|
|
- esp32
|
|
- m5stack
|
|
- gpio
|
|
- pinout
|
|
- hardware
|
|
- play
|
|
type: hardware-spec
|
|
owner: play
|
|
status: active
|
|
sources:
|
|
- "https://www.espboards.dev/esp32/m5stack-core-esp32/"
|
|
- "https://docs.m5stack.com/en/mpy/official/machine"
|
|
- "https://github.com/m5stack/m5-docs/issues/175"
|
|
---
|
|
|
|
# M5Stack Core ESP32 GPIO Pinout Reference
|
|
|
|
## Physical GPIO Ranges
|
|
|
|
Available pins: **0-19, 21-23, 25-27, 32-39**
|
|
|
|
These correspond to actual ESP32 GPIO pin numbers. Many boards use their own logical pin numbering (D0, D1, etc.) — this doc maps logical to physical.
|
|
|
|
## Reserved Pins (Do Not Use for Custom I/O)
|
|
|
|
| Pin | Reserved For | Notes |
|
|
|-----|--------------|-------|
|
|
| 0 | Boot / Button | Pulldown at boot — unsafe for output |
|
|
| 1 | TX0 | Debug serial |
|
|
| 2 | Boot / Button | Pulldown at boot |
|
|
| 3 | RX0 | Debug serial |
|
|
| 6-11 | Flash SPI | Internal flash memory — do not use |
|
|
| 12 | Boot / GPIO | Pulldown at boot — unsafe for output |
|
|
| 18, 19, 23 | SPI (LCD + TF Card) | Shared with display and SD card |
|
|
| 25 | Speaker | Connected to internal speaker amplifier |
|
|
| 21, 22 | I2C (Grove port) | SDA/SCL — available if Grove not used |
|
|
|
|
## Safe GPIO for Custom Use
|
|
|
|
| Pin | Safe Use | Notes |
|
|
|-----|----------|-------|
|
|
| 4 | General I/O | Safe if speaker not used |
|
|
| 5 | General I/O | Safe |
|
|
| 13 | General I/O | Safe |
|
|
| 14 | General I/O | Safe |
|
|
| 15 | General I/O | Safe (also MTDO) |
|
|
| 16 | General I/O | Safe |
|
|
| 17 | General I/O | Safe |
|
|
| 26 | Analog input | 12-bit ADC (also digital I/O) |
|
|
| 27 | Analog input | 12-bit ADC (also digital I/O) |
|
|
| 32-39 | Analog input | 12-bit ADC — best for sensor readings |
|
|
|
|
## I2C Bus (Grove Port)
|
|
|
|
- **SDA:** GPIO 21
|
|
- **SCL:** GPIO 22
|
|
|
|
If Grove port is not in use, pins 21/22 are available as general GPIO.
|
|
|
|
## SPI Bus
|
|
|
|
Default SPI (for LCD + SD card): GPIO 18 (CLK), 19 (MISO), 23 (MOSI). These are shared — using them for other devices may conflict with display.
|
|
|
|
Second SPI available on other pins if needed.
|
|
|
|
## Communication Protocols
|
|
|
|
- **UART:** TX on GPIO 1, RX on GPIO 3. Can remap to other pins.
|
|
- **I2C:** Default on 21/22. Can remap with `machine.SoftI2C`
|
|
- **SPI:** Default on 18/19/23. Can remap with `machine.SPI`
|
|
|
|
## Analog (ADC)
|
|
|
|
ESP32 has two ADC units:
|
|
- **ADC1:** pins 32-39 (best for sensors)
|
|
- **ADC2:** pins 0, 2, 4, 12-15 (conflicts with WiFi)
|
|
|
|
12-bit resolution (0-4095). Max input: 3.3V.
|
|
|
|
## For Chris's Projects
|
|
|
|
Based on typical M5Stack setups:
|
|
- **Grove connectors** use I2C (21/22) — leave available if using Grove sensors
|
|
- **Display conflict** means 18/19/23 are unavailable in most setups
|
|
- **Speaker on 25** — disable speaker if you need that pin
|
|
- **Analog sensors** (temperature, pressure, gas) work well on 32-39
|
|
|
|
## Common Pinouts for Chris's Projects
|
|
|
|
| Project | Pins Used | Notes |
|
|
|---------|-----------|-------|
|
|
| TILT replacement (I2C sensor) | 21 (SDA), 22 (SCL), 3.3V, GND | Uses Grove I2C |
|
|
| OLED display (I2C) | 21 (SDA), 22 (SCL) | 0.96" SSD1306 typical |
|
|
| Stepper motor (ULN2003) | Any safe GPIO x 4 | 4 control pins |
|
|
| Servo | GPIO 4 or 5 | 50Hz PWM |
|
|
| DS18B20 temp sensor | Any GPIO (1-wire) | Single wire + pullup |
|
|
|
|
---
|
|
*Research from web search — ESP32 GPIO mapping for M5Stack Core*
|
|
*Queue: research complete — moved to wiki* |