Adafruit MagTag 2.9"
ESP32-S2 board with a 2.9" E-Ink display - perfect for low-power dashboards, signage, and to-do lists.
Adafruit MagTag 2.9" Pinout
29 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | PIN_BUTTON5 | strapping | - | |
| 2 | 1 | PIN_NEOPIXELA2PWM | safe | adc | |
| 3 | 2 | A3PWM | safe | adc | |
| 4 | 3 | LIGHT_SENSORA4PWM | safe | adc | |
| 5 | 4 | BATT_MONITORA5PWM | safe | adc | |
| 6 | 5 | EPD_BUSYA6PWM | safe | adc | |
| 7 | 6 | EPD_RESETA7PWM | safe | adc | |
| 8 | 7 | EPD_DCA8PWM | safe | adc | |
| 9 | 8 | EPD_CSSSA9PWM | safe | adc · spi | |
| 10 | 9 | ACCEL_IRQA10PWM | strapping | adc | |
| 11 | 10 | A11T10PWM | strapping | adc · touch | |
| 12 | 11 | PIN_BUTTON4A12PWM | strapping | adc | |
| 13 | 12 | PIN_BUTTON3A13PWM | strapping | adc | |
| 14 | 13 | LED_BUILTINA14PWM | strapping | adc | |
| 15 | 14 | PIN_BUTTON2A15PWM | strapping | adc | |
| 16 | 15 | PIN_BUTTON1A16PWM | strapping | adc | |
| 17 | 16 | SPEAKER_SHUTDOWNA17PWM | strapping | adc | |
| 18 | 17 | A0DAC1PWM | safe | adc · dac | |
| 19 | 18 | A1DAC2PWM | safe | adc · dac | |
| 20 | 19 | A18PWM | uart | adc | |
| 21 | 20 | A19PWM | uart | adc | |
| 22 | 21 | NEOPIXEL_POWERPWM | safe | - | |
| 23 | 33 | SDAPWM | safe | i2c | |
| 24 | 34 | SCLPWM | safe | i2c | |
| 25 | 35 | MOSIPWM | safe | spi | |
| 26 | 36 | SCKPWM | safe | spi | |
| 27 | 37 | MISOPWM | safe | spi | |
| 28 | 43 | TXPWM | uart | uart | |
| 29 | 44 | RXPWM | uart | uart |
Start with these
18 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
9 pins · 4 things to knowPIN_BUTTON5GPIO0 Bootstrapping pin; selects boot mode (SPI Boot vs UART Download). Strapping
Must be pulled high for normal boot; pulling low at reset enters bootloader (download mode). Also serves as SPI flash data-in (SPID) line when using external flash memory.
ACCEL_IRQGPIO9A11GPIO10PIN_BUTTON4GPIO11PIN_BUTTON3GPIO12LED_BUILTINGPIO13PIN_BUTTON2GPIO14 General-purpose SPI2 (FSPI) IO MUX pins Other
IO MUX pin of the general-purpose SPI2 (FSPI) bus, not of the in-package flash - that sits on GPIO26-32. The datasheet does not restrict it, so it is only taken if your board wires flash, an SD card or a display to FSPI.
- ACCEL_IRQGeneral-purpose SPI2 (FSPI) IO MUX pin - hold/data line (FSPIHD)
- A11General-purpose SPI2 (FSPI) IO MUX pin - chip select (FSPICS0)
- PIN_BUTTON4General-purpose SPI2 (FSPI) IO MUX pin - data in (FSPID)
- PIN_BUTTON3General-purpose SPI2 (FSPI) IO MUX pin - clock (FSPICLK)
- LED_BUILTINGeneral-purpose SPI2 (FSPI) IO MUX pin - data out (FSPIQ)
- PIN_BUTTON2General-purpose SPI2 (FSPI) IO MUX pin - write-protect/data line (FSPIWP)
PIN_BUTTON1GPIO15 32.768 kHz RTC crystal oscillator positive input (XTAL_32K_P); also functions as GPIO15 (U0RTS, ADC2_CH4). Other
If an external 32 kHz crystal is used for RTC, this pin is dedicated to the crystal and cannot be used as GPIO.
SPEAKER_SHUTDOWNGPIO16 32.768 kHz RTC crystal negative input (XTAL_32K_N); also GPIO16 (U0CTS, ADC2_CH5). Other
If using an external 32 kHz crystal, this pin is connected to the crystal and should not be used as general I/O.
Only if you know the tricks
2 pins · 2 things to knowA18GPIO19 USB OTG D- line (full-speed USB data -); also available as GPIO19/RTC_GPIO19 and ADC2 channel 8. USB
Used for USB communication; using this pin as general GPIO can interfere with USB functionality.
A19GPIO20 USB OTG D+ line (full-speed USB data +); also serves as GPIO20/RTC_GPIO20 and ADC2 channel 9. USB
Dedicated to USB interface; repurposing as GPIO may disrupt USB connectivity.
The Adafruit MagTag 2.9" pinout brings out 29 GPIO pins - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO33 and SCL on GPIO34; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO43 and GPIO44 cover serial logging and flashing.
On the analog side there are 20 ADC-capable pins for sensors and battery monitoring, 1 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, PIN_NEOPIXEL, A3, LIGHT_SENSOR, BATT_MONITOR and 14 more are free of any such role - the safest first picks. 9 of the exposed pins carry boot-time or system duties on the ESP32-S2 (PIN_BUTTON5, ACCEL_IRQ, A11 and 6 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32S2 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO1 - wire an LED and resistor to it
void setup() {
pinMode(1, OUTPUT);
}
void loop() {
digitalWrite(1, HIGH); delay(500);
digitalWrite(1, LOW); delay(500);
}[env:adafruit_magtag29_esp32s2]
platform = espressif32
board = esp32-s2-saola-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32-s2-saola-1 - or type it after board =.esp32:
board: esp32-s2-saola-1
variant: esp32s2
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO1
output:
- platform: gpio
pin: 1
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32-s2-saola-1 (same ids as PlatformIO).esptool.py --chip esp32s2 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32-S2 · 80 × 53.5 mm · vs other ESP32 chips →Dimensions
About this board
At its core is the ESP32-S2 - a single-core Xtensa with native USB-OTG and no Bluetooth.
Expect to pay about $34.95 - above the ~$20 typical for ESP32-S2 boards.
Onboard you'll find 2MB (QSPI) PSRAM, an ePaper 2.9" 296x128 display, a STEMMA QT connector, a speaker, an amplifier, an addressable RGB LED (GPIO1), an ambient-light sensor, battery charging via JST-PH 2.0 and D15/D14/D12/D11/Boot/Reset buttons.
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-S2 boards.
- LIS3DH triple-axis accelerometer
- M3 standoff mounts for magnetic feet (metal-surface mounting)
- Two STEMMA 3-pin JST connectors (D10, A1)
Where to buy
prices are typical street pricesResources
Similar boards
