GPIO Pinout

General Purpose Input Output (GPIO)

This page is to identify the alternate functions of the Raspberry Pi GPIO and to keep Hivetool developers from stepping on each other by reserving pins for Hivetool hardware.

Notes

1. GPIO pins are 3.3 volt logic levels and are not tolerant of 5V levels
2. These GPIO properties are set as a block, not per pin (GPIO pins 0-27 are in the same block).
   1. Can interrupt based on high/low/rise/fall/change.
   2. Schmitt Trigger Input (hysteresis) can be on or off,
   3. Output slew rate can be fast or limited, and
   4. Source and sink currents are configurable from 2 mA up to 16 mA.
3. ID_SD and ID_SC PINS are reserved for ID EEPROM.

   At boot time this I2C interface will be interrogated to look for an EEPROM that identifes the attached board and allows

   automagic setup of the GPIOs (and optionally, Linux drivers).

   DO NOT USE these pins for anything other than attaching an I2C ID EEPROM. Leave unconnected if ID EEPROM not required.

Color Legend

Color Legend
3.3 VDC Power	Serial Console/Power	I2S Audio
5 VDC Power	HX711 Scale	HAT ID ROM
Ground	DHT22 Temp/Hum.	I2C Sensors
Unused

Light green signals labeled "Unused" are available for development. Other colors are being used or are reserved for sensor families. A rain gauge and tilt sensor need to be implemented.

GPIO ordered by Header Pins

The first 26 pins on J8 (A+ and B+ models) are the same as H1 on the A and B models.

Hivetool Reserved for I2C Sensors Reserved for I2C Sensors Reserved for I2C Sensors Reserved for DHT22,7 Reserved for I2C Sensors Unused Unused Unused Unused Unused Unused Unused Unused Reserved ID EEPROM Unused Unused Unused Reserved I2S Unused Unused

R Pi 3.3 VDC Power GPIO 2 I2C SDA GPIO 3 I2C SCL GPIO 4 GPCLK0 Ground GPIO 17 GPIO 27 GPIO 22 3.3 VDC Power GPIO 10 SPI0 MOSI GPIO 09 SPI0 MISO GPIO 11 SPI0 SCLK Ground GPIO 0 I2C0_SDA GPIO 5 GPCLK1 GPIO 6 GPCLK2 GPIO 13 PWM1 GPIO 19 PCM_FS GPIO 26 Ground

J8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

R Pi 5 VDC Power 5 VDC Power Ground GPIO 14 TXD GPIO 15 RXD GPIO 18 PCM_CLK Ground GPIO 23 GPIO 24 Ground GPIO 25 GPIO 8 SPI0_CE0 GPIO 7 SPI0_CE1 GPIO 1 I2C0_SCL Ground GPIO 12 PWM0 Ground GPIO 16 GPIO 20 PCM_DIN GPIO 21 PCM DOUT

Hivetool Reserved Power HX711 Reserved Power Reserved Ground Reserved serial console Reserved serial console Reserved I2S Reserved HX711 Reserved HX711 Reserved HX711 Unused Reserved for DHT22,6 Unused Unused Reserved ID EEPROM Unused Unused Unused Unused Reserved I2S Reserved I2S

GPIO ordered by Signal Name

Signal	Alt Function	J8	H1	H5
3.3 VDC Power		1	1	3
3.3 VDC Power		17	17
5 VDC Power		2	2	1
5 VDC Power		4	4
GPIO 0	I2C0_SDA	27
GPIO 1	I2C0_SCL	28
GPIO 2	I2C1 SDA	3	3
GPIO 3	I2C1 SCL	5	5
GPIO 4	GPCLK0	7	7
GPIO 5	GPCLK1	29
GPIO 6	GPCLK2	31
GPIO 7	SPI0 CE1	26	26
GPIO 8	SPI0 CE0	24	24
GPIO 9	SPI0 MISO	21	21
GPIO 10	SPI0 MOSI	19	19
GPIO 11	SPI0 SCLK	23	23
GPIO 12	PWM0	32
GPIO 13	PWM1	33
GPIO 14	UART0 TXD	8	8
GPIO 15	UART0 RXD	10	10
GPIO 16		36
GPIO 17		11	11
GPIO 18	PCM_CLK	12	12
GPIO 19	PCM_FS	35
GPIO 20	PCM_DIN	38
GPIO 21	PCM DOUT	40
GPIO 22		15	15
GPIO 23		16	16
GPIO 24		18	18
GPIO 25		22	22
GPIO 26		37
GPIO 27		13	13
GPIO 28	I2C0_SDA			3
GPIO 29	I2C0_SCL			4
GPIO 30				5
GPIO 31				6
Ground		6	6	7
Ground		9	9	8
Ground		14	14
Ground		20	20
Ground		25	25
Ground		30
Ground		34
Ground		39

Resources

1. eLinux.org RPi Low-level peripherals
2. Raspberry Pi B+ Reduced Schematic
3. eLinux.org BCM2835 GPIO functions
4. BCM2835 Data Sheet (Manual)
5. eLinux.org BCM2835 datasheet errata
6. Hardware attached on Top
7. WiringPi Alternate GPIO Assignments