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Quick reference for GPIO assignments on the ED1 Citilab Board.

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GPIO assignment table

GPIOFunctionIDDirNotes
0Boot/Flash-IBoot mode select
2Touch Leftbtn_leftICapacitive touch
4Touch Upbtn_upICapacitive touch
5TFT CSinternal_displayOSPI chip select
9TFT DCinternal_displayOData/Command
10TFT Resetinternal_displayODisplay reset
12LED Matrixled_matrix_lightOWS2812 data
13Touch Downbtn_downICapacitive touch
14Touch Xbtn_xICapacitive touch
15Touch OKbtn_okICapacitive touch
18SPI CLKspiOSPI clock
19SPI MISOspiISPI data in
21I2C SDAbus_i2cI/OI2C data
22I2C SCLbus_i2cOI2C clock
23SPI MOSIspiOSPI data out
26Buzzerbuzzer_outputOPAM8301 amp
27Touch Rightbtn_rightICapacitive touch
34Light Sensorlight_sensorIADC input
32IR TXremote_transmitterORev 1.0 only
33/35IR RXremote_receiverIGPIO33 Rev 1.0, GPIO35 Rev 2.3
ID = ESPHome component ID. Dir = I (input), O (output), I/O (bidirectional).

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Bus assignments

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SPI bus

GPIO18 (CLK), GPIO23 (MOSI), GPIO19 (MISO). Used by TFT Display (ST7735).

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I2C bus

GPIO21 (SDA), GPIO22 (SCL). Rev 2.3:
DeviceAddressFunction
MXC6655XA0x15Accelerometer
MCP230090x20I/O Expander (stepper motors)
Rev 1.0:
DeviceAddressFunction
LIS3DH0x19Accelerometer
MCP230170x20I/O Expander (16 GPIO pins)

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MCP23009 GPIO mapping (stepper motors)

GPIOCoilDriverMotor
GP0DULN2004A U8M2
GP1CULN2004A U8M2
GP2BULN2004A U8M2
GP3AULN2004A U8M2
GP4DULN2004A U7M1
GP5CULN2004A U7M1
GP6BULN2004A U7M1
GP7AULN2004A U7M1

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Touch button mapping

UP
GPIO4
LEFT
GPIO2
TFT Display
RIGHT
GPIO27
OK
GPIO15
X
GPIO14
DOWN
GPIO13

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Analog inputs

GPIOFunctionADCAttenuation
34Light SensorADC1_CH612dB (0–3.3V)

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LED matrix

  • Data Pin: GPIO12
  • Type: WS2812X (GRB color order)
  • Count: 256 LEDs (32 columns x 8 rows)
  • Layout: Serpentine (zigzag) pattern

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Pixel mapping

Column:  0   1   2   3  ...
Row 0:   0   15  16  31 ...
Row 1:   1   14  17  30 ...
Row 2:   2   13  18  29 ...
...
Row 7:   7   8   23  24 ...
Formula: 
if (x % 2 == 0)
    pixel = (x * 8) + y;
else
    pixel = (x * 8) + (7 - y);

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Expansion connectors

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Analog ports - J5 (left side)

Input-only ADC pins, directly connected to ESP32. Active-low.
PortGPIOADCNotes
A1GPIO36ADC1_CH0SVP
A2GPIO37ADC1_CH1-
A3GPIO38ADC1_CH2-
A4GPIO39ADC1_CH3SVN
All analog ports share a 3-pin connector: S (signal), + (3.3V), - (GND).

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Digital ports - J2 (right side)

PortGPIOADCNotes
D1GPIO12ADC2_CH5LED matrix data
D2GPIO25ADC2_CH8DAC1
D3GPIO32ADC1_CH4-
D4GPIO26ADC2_CH9Buzzer output
All digital ports share a 3-pin connector: S (signal), + (5V), - (GND). Note: D1 (GPIO12) and D4 (GPIO26) are used internally. D2 (GPIO25) and D3 (GPIO32) are available for external use.

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I2C/serial - J6 (bottom left)

PinLabelGPIOFunction
1DAGPIO21I2C SDA
2CLGPIO22I2C SCL
3TXGPIO1UART TX
4RXGPIO3UART RX

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Grove connector (J11)

PinSignalConnection
1VDD333.3V
2GNDGround
3SDAGPIO21
4SCLGPIO22

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Stepper motor connectors

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M1 & M2 (28BYJ-48)

PinSignal
1Coil A
2Coil B
3Coil C
4Coil D
5VDD5 (common)
Controlled via MCP23009 I/O expander and ULN2004A drivers.

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Reserved/internal GPIOs

These GPIOs are used internally by the ESP32 or board hardware:
GPIOInternal Use
6-11Flash (do not use)
16, 17Flash CS/SDO
36, 39Sensor VP/VN