View source for Pi Zero GPIO mapping (Delta/Delta-B)

{| class="wikitable floatright"
|-
! scope="col"| Legend
|-
| style="background-color: red;text-align:center" | 3.3V Power
|-
| style="background-color: fuchsia;text-align:center" | 3.5V-5V power
|-
| style="color: white;background-color: black;text-align:center" | GND
|-
| style="background-color: yellow;text-align:center" | Audio pins
|-
| style="color: white;background-color: blue;text-align:center" | 1.3" OLED display connections
|-
| style="background-color: aqua;text-align:center" | Expansion header pins
|-
| style="background-color: lime;text-align:center" | ESP8266 SDIO pins
|-
| style="background-color: orange;text-align:center" | ATMega, MCP23017 and GSM connections
|}


{| class="wikitable"
|-
! scope="col"| Pin Number
! scope="col"| Pin name
! scope="col"| Function
! scope="col"| Used For
|-
| style="text-align:right;background-color: red;" | 1
| style="background-color: red;" | 3V3
| style="background-color: red;" | 3V3
| style="background-color: red;" | Power for ESP8266/display
|-
| style="text-align:right;background-color: fuchsia" | 2
| style="background-color: fuchsia;" | VSYS
| style="background-color: fuchsia;" | VSYS
| style="background-color: fuchsia;" | VSYS in, VBAT sensing with ATMega
|-
| style="text-align:right;background-color: orange" | 3
| style="background-color: orange;" | GPIO2
| style="background-color: orange;" | SDA
| style="background-color: orange;" | I2C - ATMega, MCP23017, expansion header, testpoints
|-
| style="text-align:right;background-color: fuchsia" | 4
| style="background-color: fuchsia;" | VSYS
| style="background-color: fuchsia;" | VSYS
| style="background-color: fuchsia;" | VSYS in, VSYS sensing with ATMega
|-
| style="text-align:right;background-color: orange" | 5
| style="background-color: orange;" | GPIO3
| style="background-color: orange;" | SCL
| style="background-color: orange;" | I2C - ATMega, MCP23017, expansion header, testpoints
|-
| style="color: white;text-align:right;background-color: black" | 6
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: aqua" | 7
| style="background-color: aqua;" | GPIO4
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | IR TX
|-
| style="text-align:right;background-color: orange" | 8
| style="background-color: orange;" | GPIO14
| style="background-color: orange;" | RXD
| style="background-color: orange;" | GSM UART TXD
|-
| style="color: white;text-align:right;background-color: black" | 9
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: orange" | 10
| style="background-color: orange;" | GPIO15
| style="background-color: orange;" | TXD
| style="background-color: orange;" | GSM UART RXD
|-
| style="text-align:right;background-color: aqua" | 11
| style="background-color: aqua;" | GPIO17
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | Expansion header / SPI1 / IR RX
|-
| style="text-align:right;background-color: aqua" | 12
| style="background-color: aqua;" | GPIO18
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | Expansion Header / I2S / SPI1
|-
| style="text-align:right;background-color: lime" | 13
| style="background-color: lime;" | GPIO27
| style="background-color: lime;" | SD_D3
| style="background-color: lime;" | ESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="color: white;text-align:right;background-color: black" | 14
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="background-color: lime;text-align:right;" | 15
| style="background-color: lime;" | GPIO22
| style="background-color: lime;" | SD_CLK
| style="background-color: lime;" | ESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="background-color: lime;text-align:right;" | 16
| style="background-color: lime;" | GPIO23
| style="background-color: lime;" | SD_CMD
| style="background-color: lime;" | IESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="background-color: red;text-align:right;" | 17
| style="background-color: red;" | 3V3
| style="background-color: red;" | 3V3
| style="background-color: red;" | Power for ATMega
|-
| style="background-color: lime;text-align:right;" | 18
| style="background-color: lime;" | GPIO24
| style="background-color: lime;" | SD_D0
| style="background-color: lime;" | ESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="color: white;text-align:right;background-color: blue" | 19
| style="color: white;background-color: blue;" | GPIO10
| style="color: white;background-color: blue;" | SPI_MOSI
| style="color: white;background-color: blue;" | Display SPI interface, expansion header
|-
| style="color: white;text-align:right;background-color: black" | 20
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: aqua" | 21
| style="background-color: aqua;" | GPIO9
| style="background-color: aqua;" | SPI_MISO
| style="background-color: aqua;" | Expansion header - SPI
|-
| style="text-align:right;background-color: lime" | 22
| style="background-color: lime;" | GPIO25
| style="background-color: lime;" | SD_D1
| style="background-color: lime;" | ESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="color: white;text-align:right;background-color: blue" | 23
| style="color: white;background-color: blue;" | GPIO11
| style="color: white;background-color: blue;" | SCK
| style="color: white;background-color: blue;" | Display SPI interface, expansion header
|-
| style="color: white;text-align:right;background-color: blue" | 24
| style="color: white;background-color: blue;" | GPIO8
| style="color: white;background-color: blue;" | SPI_CSO
| style="color: white;background-color: blue;" | Display SPI interface
|-
| style="color: white;text-align:right;background-color: black" | 25
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: aqua" | 26
| style="background-color: aqua;" | GPIO7
| style="background-color: aqua;" | SPI_CS1
| style="background-color: aqua;" | Expansion header - SPI
|-
| style="text-align:right;background-color: lime" | 27
| style="background-color: lime;" | GPIO0
| style="background-color: lime;" | SD_RST
| style="background-color: lime;" | EEPROM SDA / ESP8266 RESET pin / ESP-socket GPIO expansion
|-
| style="text-align:right;background-color: orange" | 28
| style="background-color: orange;" | GPIO1
| style="background-color: orange;" | MCP_INT
| style="background-color: orange;" | EEPROM SCL / MCP23017 interrupt pin
|-
| style="color: white;text-align:right;background-color: blue" | 29
| style="color: white;background-color: blue;" | GPIO5
| style="color: white;background-color: blue;" | DP_RST
| style="color: white;background-color: blue;" | Keypad GPIO / Display SPI interface
|-
| style="color: white;text-align:right;background-color: black" | 30
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="color: white;text-align:right;background-color: blue" | 31
| style="color: white;background-color: blue;" | GPIO6
| style="color: white;background-color: blue;" | DP_DC
| style="color: white;background-color: blue;" | Display SPI interface
|-
| style="text-align:right;background-color: yellow" | 32
| style="background-color: yellow;" | GPIO12
| style="background-color: yellow;" | AUDIO_0
| style="background-color: yellow;" | PWM audio
|-
| style="text-align:right;background-color: yellow" | 33
| style="background-color: yellow;" | GPIO13
| style="background-color: yellow;" | AUDIO_1
| style="background-color: yellow;" | PWM audio
|-
| style="color: white;text-align:right;background-color: black" | 34
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: aqua" | 35
| style="background-color: aqua;" | GPIO19
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | Expansion header / I2S / SPI1
|-
| style="text-align:right;background-color: orange" | 36
| style="background-color: orange;" | GPIO16
| style="background-color: orange;" | KEYPAD_INT
| style="background-color: orange;" | ATMega328p interrupt pin
|-
| style="text-align:right;background-color: lime" | 37
| style="background-color: lime;" | GPIO26
| style="background-color: lime;" | SD_D2
| style="background-color: lime;" | ESP8266 SDIO pin / ESP-socket GPIO expansion
|-
| style="text-align:right;background-color: aqua" | 38
| style="background-color: aqua;" | GPIO20
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | Expansion header / I2S / SPI1
|-
| style="color: white;text-align:right;background-color: black" | 39
| style="color: white;background-color: black;" | GND
| style="color: white; background-color: black;" | GND
| style="color: white;background-color: black;" | Ground
|-
| style="text-align:right;background-color: aqua" | 40
| style="background-color: aqua;" | GPIO21
| style="background-color: aqua;" | GPIO
| style="background-color: aqua;" | Expansion header /I2S / SPI1
|}