Raspberry Pi Symbol
Definition: The Raspberry Pi symbol represents the Raspberry Pi single-board computer (SBC) in schematic and wiring diagrams, depicted as a rectangle labelled 'Raspberry Pi' with GPIO pins (GPIO2, GPIO3, GPIO4, GPIO17, GPIO27, GPIO22, GND, 3.3V, 5V, GPIO18) along the top edge and a USB connector port on the bottom-right edge, following IEEE 315-1975 rectangular IC block notation for complex integrated modules.
Also known as: RPi, Raspberry Pi SBC, Pi, Raspberry Pi module, linux SBC, ARM board.
What the Raspberry Pi symbol means
The Raspberry Pi symbol in a circuit or wiring diagram indicates the presence of a Raspberry Pi single-board computer as a component or subsystem in the design. The Raspberry Pi is a series of low-cost credit-card-sized computers based on ARM processors running Linux (Raspberry Pi OS or other distributions), used extensively in embedded systems, IoT projects, education, industrial control, and prototyping.
The symbol communicates to the schematic reader the input/output interface points through which the Raspberry Pi interacts with the surrounding circuitry — GPIO pins for digital I/O, I2C, SPI, and UART communication; power supply pins for 3.3 V and 5 V rails; and USB for peripherals and data transfer. The Raspberry Pi is designed and produced by the Raspberry Pi Foundation (UK), and the GPIO header follows a defined pin-numbering standard documented in the BCM2835/2836/2837/2711 chip datasheets.
How to identify the Raspberry Pi symbol
The Raspberry Pi symbol is drawn as a large rectangle with 'Raspberry' written on one line and 'Pi' on the next inside the box. A series of short vertical lines emerge from the top edge of the rectangle, representing the GPIO header pins (GPIO2, GPIO3, GPIO4, GPIO17, GPIO27, GPIO22, GND, 3.3V, 5V, GPIO18 and more). A smaller rectangle on the bottom-right edge represents the USB connector port. The large rectangular block style with labelled peripheral pins follows IEEE 315-1975 IC block notation used for microcontrollers and complex modules.
Function in a circuit
The Raspberry Pi single-board computer integrates an ARM Cortex-A series processor, RAM (256 MB to 8 GB depending on model), GPU, USB ports, HDMI output, Ethernet, Wi-Fi (model-dependent), microSD card slot, and a 40-pin GPIO header on a single PCB. The GPIO header provides 28 user-accessible digital I/O pins that can be configured as general-purpose digital input/output, I2C (GPIO2=SDA, GPIO3=SCL), SPI (GPIO10=MOSI, GPIO9=MISO, GPIO11=SCLK, GPIO8=CE0), UART (GPIO14=TXD, GPIO15=RXD), and PWM outputs. The 3.3V and 5V pins supply power to external circuits; the GND pins complete the circuit. The Raspberry Pi is powered via USB-C (Pi 4/5) or micro-USB (Pi 3/Zero) at 5 V DC.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60617 does not define a Raspberry Pi symbol. The device is represented using IEC 60617-13 general functional block notation (rectangle) with labelled interface pins. The GPIO pin functions are defined by the Broadcom BCM2711 (Pi 4) or BCM2837B0 (Pi 3) datasheet and the Raspberry Pi GPIO documentation. |
|---|---|
| ANSI/IEEE 315 | IEEE 315-1975 (ANSI Y32.2) defines the rectangular IC block symbol convention used for the Raspberry Pi in schematics. GPIO pin assignments and electrical specifications are governed by Raspberry Pi Foundation documentation, not a formal ANSI electrical standard. |
| Key difference | Both IEC and ANSI/IEEE use rectangular block notation for the Raspberry Pi symbol; there is no meaningful difference in symbol representation between the two standards. The Raspberry Pi Foundation's own GPIO documentation and BCM chip datasheets are the authoritative technical references for pin functions and electrical ratings. |
Terminals / pins
| Pin | Name |
|---|---|
| gpio2 | GPIO2 |
| gpio3 | GPIO3 |
| gpio4 | GPIO4 |
| gpio17 | GPIO17 |
| gpio27 | GPIO27 |
| gpio22 | GPIO22 |
| gnd | GND |
| 3v3 | 3.3V |
| 5v | 5V |
| gpio18 | GPIO18 |
| usb | USB |
Typical values
Supply voltage: 5 V DC ±5% at GPIO 5V pins or USB power input. GPIO logic levels: 3.3 V (HIGH), 0 V (LOW) — NOT 5 V tolerant. GPIO maximum current: 16 mA per pin, 50 mA total GPIO bank. 3.3V pin: up to 50 mA output. 5V pin: limited by USB power supply (typically 3 A for Pi 4 with official PSU). I2C speed: 100 kHz or 400 kHz. SPI speed: up to 125 MHz.
Where the Raspberry Pi symbol is used
- IoT gateway devices connecting sensors, actuators, and cloud services via Wi-Fi or Ethernet in home and industrial automation
- Embedded Linux control systems for robotics, CNC machines, and lab automation requiring USB, network, and GPIO simultaneously
- Digital signage and kiosk displays using HDMI output with GPIO buttons and sensor inputs
- Educational electronics and programming platforms for teaching Python, Linux, and hardware interfacing
- Home automation hubs running Home Assistant or similar platforms controlling lighting, HVAC, and security systems
- Network attached storage (NAS) and VPN server nodes using USB 3.0 storage and Gigabit Ethernet (Pi 4)
Example
In a greenhouse monitoring system schematic, the Raspberry Pi symbol shows GPIO4 connected to a DHT11 temperature/humidity sensor data line, GPIO2 (I2C SDA) and GPIO3 (I2C SCL) connected to a BMP280 pressure sensor, GND connected to the common ground rail, and 3.3V supplying the sensor VCC rails, while the USB pin connects to a 4G modem for cloud data upload.
Key facts
- The Raspberry Pi symbol is a rectangle labelled 'Raspberry Pi' with GPIO header pins (GPIO2, GPIO3, GPIO4, GPIO17, GPIO27, GPIO22, GND, 3.3V, 5V, GPIO18, and more) along the top edge and a USB connector on the right, following IEEE 315-1975 IC block notation.
- Raspberry Pi GPIO pins operate at 3.3 V logic levels — they are NOT 5 V tolerant. Connecting 5 V signals directly to GPIO pins will damage the BCM processor without a level shifter.
- The standard 40-pin GPIO header (J8) on Raspberry Pi models 2, 3, 4, and 5 includes: 28 GPIO pins, 2× 5V pins, 2× 3.3V pins, and 8× GND pins. Pin 1 is the 3.3V power pin in the corner nearest the SD card.
- GPIO pins can be configured as I2C (GPIO2/GPIO3), SPI (GPIO10/GPIO9/GPIO11/GPIO8/GPIO7), UART (GPIO14/GPIO15), I2S audio, PWM, and general-purpose digital I/O via software configuration.
- The Raspberry Pi is powered by 5 V DC via USB-C (Pi 4/5) requiring at least 3 A; the official Raspberry Pi power supply is recommended to avoid under-voltage warnings and CPU throttling.
- Raspberry Pi models are distinguished by processor: Pi Zero (BCM2835, 1 GHz single-core), Pi 3B+ (BCM2837B0, 1.4 GHz quad-core), Pi 4B (BCM2711, 1.5–1.8 GHz quad-core A72), Pi 5 (BCM2712, 2.4 GHz quad-core A76).
- The 3.3V GPIO power pin can source up to 50 mA total for external circuits; for higher current loads a separate 3.3V regulator powered from the 5V pin is recommended to avoid damaging the on-board regulator.
Frequently asked questions
What does the Raspberry Pi symbol look like in a circuit diagram?
The Raspberry Pi symbol is a large rectangle labelled 'Raspberry Pi' with a row of short lines along the top edge representing the GPIO header pins (labelled GPIO2, GPIO3, GPIO4, GPIO17, GPIO27, GPIO22, GND, 3.3V, 5V, GPIO18, etc.) and a smaller rectangle on the bottom-right representing the USB connector.
What does the Raspberry Pi symbol mean in a schematic?
The Raspberry Pi symbol represents the single-board computer as a functional block in a circuit. It shows the available interface pins — GPIO, power, and USB — through which the Raspberry Pi connects to sensors, actuators, displays, and power supplies in the surrounding circuit.
What voltage are Raspberry Pi GPIO pins?
Raspberry Pi GPIO pins operate at 3.3 V logic levels. A HIGH output is 3.3 V; a LOW is 0 V. GPIO inputs are NOT 5 V tolerant — applying 5 V signals directly to GPIO pins will damage the BCM processor. A level shifter (e.g. 74AHCT125 or BSS138-based) is required to interface with 5 V devices.
What are the main GPIO pin functions on a Raspberry Pi?
GPIO2 and GPIO3 are the I2C SDA and SCL pins (400 kHz fast-mode). GPIO14 and GPIO15 are UART TXD and RXD. GPIO10, GPIO9, GPIO11, GPIO8 are SPI MOSI, MISO, SCLK, and CE0. GPIO12 and GPIO13 support hardware PWM. All remaining GPIO pins can be used as general-purpose digital input or output.
How much current can Raspberry Pi GPIO pins supply?
Each individual Raspberry Pi GPIO pin can source or sink a maximum of 16 mA. The total current draw from all GPIO pins simultaneously must not exceed 50 mA. For loads requiring more current (LEDs, relays, motors), use a transistor, MOSFET, or dedicated driver IC to buffer the GPIO output.
What power supply does a Raspberry Pi require?
Raspberry Pi 4 and 5 require 5 V DC supplied via USB-C at a minimum of 3 A (15 W) for the official power supply. Pi 3B+ uses 5 V micro-USB at 2.5 A. Using an undersized supply causes under-voltage warnings (lightning bolt icon on display) and CPU throttling. The 5V GPIO pins can provide supplemental power to external circuits limited by the USB PSU capacity.
What is the designator used for a Raspberry Pi in schematics?
A Raspberry Pi in schematics is designated U (integrated circuit/module) followed by a reference number, such as U1 or U5, per IEEE 315-1975 IC block conventions. Some designers use the prefix RPi or SBC followed by a number to specifically identify it as a single-board computer in the circuit documentation.
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