Bank 0 GPIO

GPIO0-27_VREF is the power supply for bank 0 and can be powered in the range 1.8V – 3.3V.  (Must be powered even if GPIO is not used).

GPIO0 / I2C0 SDA
GPIO1 / I2C0 SCL
GPIO2 / I2C1 SDA
​GPIO3 / I2C1 SCL
GPIO4 / GPCLK0
GPIO5 / GPCLK1
GPIO6 / GPCLK2
​GPIO​7 / SPI0 CE1
​GPIO​8 / SPI0 CE0
​GPIO​9 / SPI0 MISO
​GPIO​10 / SPI0 MOSI
​GPIO​11 / SPI0 SCLK
​GPIO​12 / PWM0
​GPIO​13 / PWM1
​GPIO​14 / UART0 TX / UART1 TX
​GPIO​15 / UART0 RX / UART1 RX
​GPIO​16 / UART0 CTS / UART1 CTS / SPI1 CE2
​GPIO​17 / UART0 RTS / UART1 RTS / SPI1 CE1
​GPIO​18 / PCM CLK / SPI1 CE0 / PWM0
​GPIO​19 / PCM FS / SPI1 MISO / PWM1
​GPIO​20 / PCM DIN / SPI1 MOSI / GPCLK0
​GPIO​21 / PCM DOUT / SPI1 SCLK / GPCLK1
​GPIO​22 / SD1 CLK
​GPIO​23 / SD1 CMD
​GPIO​24 / SD1 DAT0
​GPIO​25 / SD1 DAT1
​GPIO​26 / SD1 DAT2
GPIO27 / SD1 DAT3

Bank 1 GPIO

GPIO28-45_VREF is the power supply for bank 1 and can be powered in the range 1.8V – 3.3V.  (Must be powered even if GPIO is not used).

GPIO28 / I2C0 SDA / PCMCLK
​GPIO​29 / I2C0 SCL / PCM FS
​GPIO​30 / PCM DIN / UART0 CTS / UART1 CTS
​GPIO​31 / PCM DOUT / UART0 RTS / UART1 RTS
​GPIO​32 / GPCLK0 / UART0 TX / UART1 TX
​GPIO​33 / UART0 RX / UART1 RX
​GPIO​34 / GPCLK0
​GPIO​35 / SPI0 CE1
​GPIO​36 / SPI0 CE0 / UART0 TX
​GPIO​37 / SPI0 MISO / UART0 RX
​GPIO​38 / SPI0 MOSI / UART0 RTS
​GPIO​39 / SPI0 SCLK / UART0 CTS
​GPIO​40 / PWM0 / SPI2 MISO / UART1 TX
​GPIO​41 / PWM1 / SPI2 MOSI / UART1 RX
​GPIO​42 / GPCLK1 / SPI2 SCLK / UART1 RTS
​GPIO​43 / GPCLK2 / SPI2 CE0 / UART1 CTS
​GPIO​44 / GPCLK1 / I2C0 SDA / I2C1 SDA / SPI2 CE1
GPIO45 / PWM1 / I2C0 SCL / I2C1 SCL / SPI2 CE2

Many of the peripheral pin functions are duplicated, sometimes several times with the function assignable to different pins.

Peripheral Ports Available

UARTS's

​UART0
UART1

​I2C Ports

​I2C0
I2C1

SPI Ports

​SPI0
SPI1
SPI2

​PWM Outputs

PWM0
PWM1

​PCM Port

PCM

​Clock Outputs

​GPCLK0
​GPCLK1
GPCLK2

​SD Card Interface

SD1

Pull Up & Pull Down Resistors

All GPIOs except GPIO28, 29, 44 and 45 have weak internal pull-ups or pull-downs enabled when the device is powered on (documented in the BCM2835 peripherals document section 6.2).

It is recommended to add off-chip pulls to GPIO28, 29, 44 and 45 to make sure they do not float during power on and initial boot.

GPIO46 & GPIO47

The GPIO46_1V8 and GPIO47_1V8 pins are 1.8V IO only and are reserved for special functions (HDMI hot plug detect and boot control respectively). Don’t use these pins for any other purpose, as the software for the Compute Module will always expect these pins to have these special functions. If they are unused leave them unconnected.