Pin Reference

Axiometa Pixie M1
ESP32-S3 • USB-C • NeoPixel • Touch Capable
Power
Ground
GPIO
ADC
Touch
PWM
UART
GND
Ground
5V
5.0V
3V3
3.3V
GND
Ground
RST
Reset
0
Boot/User Btn
44
RX
43
TX
14
T A P SCK
13
T A P MISO
12
T A P MOSI
Pixie
M1
11
LED P A T SCL
10
P A T SDA
9
P A T
8
P A T
7
P A T
6
P A T
5
P A T
4
P A T
3
P A T
2
P A T
1
P A T CS
Default Peripherals
I2C SDA: GPIO 10
I2C SCL: GPIO 11
SPI MOSI: GPIO 12
SPI MISO: GPIO 13
SPI SCK: GPIO 14
SPI CS: GPIO 1
UART TX: GPIO 43
UART RX: GPIO 44
Notes
NeoPixel on GPIO 21 (directly controllable)
Activity LED on GPIO 11 (directly controllable)
User button on GPIO 0 (active LOW)
All numbered GPIOs support PWM, ADC, and Touch
ESP32-WROOM-32
ESP32 • 38-pin DevKit • WiFi + Bluetooth
Power
Ground
GPIO
ADC
Touch
Caution
3V3
3.3V
EN
Reset
36
A
VP, input only
39
A
VN, input only
34
A
input only
35
A
input only
32
AT
33
AT
25
A
DAC1
26
A
DAC2
27
AT
14
AT
12
AT
boot fail if HIGH
GND
13
AT
9
Flash - don't use
10
Flash - don't use
11
Flash - don't use
5V
VIN
ESP32
DevKit
GND
23
MOSI
22
SCL
1
TX
3
RX
21
SDA
GND
19
MISO
18
SCK
5
CS
PWM at boot
17
TX2
16
RX2
4
AT
0
AT
Boot
2
ATLED
15
AT
PWM at boot
8
Flash - don't use
7
Flash - don't use
6
Flash - don't use
Default Peripherals
I2C SDA: GPIO 21
I2C SCL: GPIO 22
SPI MOSI: GPIO 23
SPI MISO: GPIO 19
SPI SCK: GPIO 18
SPI CS: GPIO 5
UART TX: GPIO 1
UART RX: GPIO 3
Notes
GPIO 6-11: Connected to flash - do not use
GPIO 12: Must be LOW during boot
GPIO 34-39: Input only, no pull-up/down
GPIO 2: Often connected to onboard LED
ADC2 pins unavailable when WiFi active
Wemos D1 Mini
ESP8266 • Compact • WiFi
Power
Ground
GPIO
ADC
Caution
RST
Reset
A0
A
ADC (0-1V)
D0
GPIO16, wake
D5
SCK
GPIO14
D6
MISO
GPIO12
D7
MOSI
GPIO13
D8
CS
GPIO15, pull-down
3V3
3.3V out
D1
Mini
TX
TX
GPIO1
RX
RX
GPIO3
D1
SCL
GPIO5
D2
SDA
GPIO4
D3
GPIO0, flash btn
D4
LED
GPIO2, pull-up
GND
5V
VIN
Default Peripherals
I2C SDA: D2 (GPIO4)
I2C SCL: D1 (GPIO5)
SPI MOSI: D7 (GPIO13)
SPI MISO: D6 (GPIO12)
SPI SCK: D5 (GPIO14)
SPI CS: D8 (GPIO15)
Notes
D3 (GPIO0): Pulled HIGH, boot fails if LOW
D8 (GPIO15): Pulled LOW, boot fails if HIGH
D4 (GPIO2): Onboard LED (active LOW)
D0 (GPIO16): Can wake from deep sleep
A0: Only ADC, 0-1V range (3.3V with divider)
Raspberry Pi Pico
RP2040 • Dual Core ARM • 264KB RAM
Power
Ground
GPIO
ADC
PWM
0
TXP
1
RXP
GND
2
SDAP
3
SCLP
4
RXP
5
CSP
GND
6
SCKP
7
TXP
8
P
9
P
GND
10
P
11
P
12
P
13
P
GND
14
P
15
P
Pi
Pico
VBUS
5V USB
VSYS
1.8-5.5V in
GND
3V3_EN
3V3
3.3V out
ADC_REF
28
A2
GND
27
A1
26
A0
RUN
Reset
22
P
GND
21
P
20
P
19
TXP
18
SCKP
GND
17
CSP
16
RXP
Default Peripherals
I2C0 SDA: GPIO 4
I2C0 SCL: GPIO 5
SPI0 RX: GPIO 16
SPI0 TX: GPIO 19
SPI0 SCK: GPIO 18
SPI0 CS: GPIO 17
UART0 TX: GPIO 0
UART0 RX: GPIO 1
Notes
All GPIOs support PWM (16 channels)
GPIO 25: Onboard LED (directly controllable)
ADC: 12-bit, 3 external + 1 internal temp sensor
PIO: Programmable I/O for custom protocols
Hold BOOTSEL during power-on for USB mass storage
Arduino Nano
ATmega328P • 5V Logic • 16MHz
Power
Ground
Digital
Analog
PWM
D13
SCKLED
D12
MISO
D11
MOSIP
D10
CSP
D9
P
D8
D7
D6
P
D5
P
D4
D3
P
INT1
D2
INT0
GND
RST
D0
RX
Arduino
Nano
VIN
7-12V
GND
RST
5V
5V out
A7
A
A6
A
A5
ASCL
A4
ASDA
A3
A
A2
A
A1
A
A0
A
AREF
3V3
3.3V out
D1
TX
Default Peripherals
I2C SDA: A4
I2C SCL: A5
SPI MOSI: D11
SPI MISO: D12
SPI SCK: D13
SPI CS: D10
Serial TX: D1
Serial RX: D0
Notes
5V logic - use level shifter for 3.3V devices
D13: Onboard LED (also SPI SCK)
PWM pins: D3, D5, D6, D9, D10, D11
External interrupts: D2 (INT0), D3 (INT1)
A6, A7: Analog input only, no digital
ESP32-C3 SuperMini
ESP32-C3 • RISC-V • USB-C • Ultra Compact
Power
Ground
GPIO
ADC
PWM
0
AP
1
AP
2
AP
Boot
3
AP
4
APSDA
5
PSCL
6
PSCK
7
PMOSI
C3
Mini
10
PMISO
20
RXP
21
TXP
8
PLED
9
PBOOT
5V
VIN
3V3
3.3V out
GND
Default Peripherals
I2C SDA: GPIO 4
I2C SCL: GPIO 5
SPI MOSI: GPIO 7
SPI MISO: GPIO 10
SPI SCK: GPIO 6
UART TX: GPIO 21
UART RX: GPIO 20
LED: GPIO 8
Notes
GPIO 8: Onboard LED (directly controllable)
GPIO 9: Boot button (hold LOW to enter bootloader)
GPIO 2: Strapping pin - avoid external pull-down
Native USB - no external USB-UART chip
All GPIOs support PWM
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