Back to: Raspberry Pi
CPU, RAM and hard storage
Like any computer, Raspberry Pi is made up of various components, each of which has a role to play in making it work. The first, and arguably most important, of these can be found just above the centre point on the top side of the board, covered in a metal cap: the system-on-chip (SoC) (see image above BCM2712 processor).
The name system-on-chip is a great indicator of what you would find if you prised the metal cover off: a silicon chip, known as an integrated circuit, which contains the bulk of Raspberry Pi’s system. This includes the central processing unit (CPU), commonly thought of as the ‘brain’ of a computer, and the graphics processing unit (GPU), which handles the visual side of things.
A brain is no good without memory, however, and just above the SoC you’ll find exactly that: another chip, which looks like a small, black, plastic square (SRAM 8Gb). This is Raspberry Pi’s random access memory (RAM). When you’re working on Raspberry Pi, it’s the RAM that holds what you’re doing; only when you save your work will it be written to the microSD card mounted underneath (hard storage, like a HDD or SSD or USB drive). Together, these components form Raspberry Pi’s volatile and non-volatile memories: the volatile RAM loses its contents whenever Raspberry Pi is powered off, while the non-volatile microSD card keeps its contents.
Wireless communications
The component labelled Dual Band 802.11ac Wireless and Bluetooth 5 is the radio, the component which gives Raspberry Pi the ability to communicate with devices wirelessly. The radio itself acts as two main components, in fact: a WiFi radio, for connecting to computer networks; and a Bluetooth radio, for connecting to peripherals like mice and for sending data to or receiving data from nearby smart devices like sensors or smartphones.
Other components
Another black, plastic-covered chip can be seen to the bottom edge of the board, just above the USB-C power connector. This is the power management integrated circuit (PMIC); it takes power from the USB-C port and turns it into the power needed for the Raspberry Pi to run.
The ethernet transceiver handles Raspberry Pi’s Ethernet network port.
Raspberry Pi’s ports
Raspberry Pi has a range of ports, starting with four Universal Serial Bus (USB) ports to the middle and right-hand side of the bottom edge. These ports let you connect any USB-compatible peripheral, from keyboards and mice to digital cameras and flash drives, to Raspberry Pi. Speaking technically, there are two types of USB ports: the ones with black parts inside are USB 2.0 ports, based on version two of the Universal Serial Bus standard; the ones with blue parts are faster USB 3.0 ports, based on the newer version three.
Next to the USB ports is an Ethernet port, also known as a network port . You can use this port to connect your Raspberry Pi to a wired computer network with a cable that uses what is known as an RJ45 connector. If you look closely at the Ethernet port, you’ll see two light-emitting diodes (LEDs) at the bottom. These are status lights which, when lit or blinking, let you know the connection is working.
Just to the left of the Ethernet port, on the bottom edge of Raspberry Pi, is a Power-over-Ethernet (PoE) connector. This connector, when paired with the Raspberry Pi 5 PoE+ HAT — Hardware Attached on Top, a special add-on board designed for Raspberry Pi — and a suitable PoE-capable network switch, lets you power Raspberry Pi from its Ethernet port without having to connect anything to the USB Type-C connector. The same connector is also available on Raspberry Pi 4, though in a different location; Raspberry Pi 4 and Raspberry Pi 5 use different HATs for PoE support.
To the left of the PoE connector are a pair of connectors with plastic flaps you can pull up; these are the camera and display connectors, also known as the Camera Serial Interface (CSI) and Display Serial Interface (DSI) ports. You can use these connectors to connect a DSI-compatible display like the Raspberry Pi Touchscreen Display or the specially designed Raspberry Pi Camera Module family.
To the left of the camera and display connectors, still on the bottom edge of the board, are the micro High Definition Multimedia Interface (micro HDMI) ports, which are smaller versions of the connectors you can find on a games console, set-top box, or TV. The ‘multimedia’ part of its name means that it carries both audio and video signals, while ‘high-definition’ means you can expect excellent quality from both signals. You’ll use these micro HDMI ports to connect Raspberry Pi to one or two display devices, such as a computer monitor, TV, or projector.
To the left of the micro HDMI ports is another small connector labelled ‘BAT’, where you can connect a small battery to keep Raspberry Pi’s real-time clock (RTC) ticking, even when it’s disconnected from its power supply. You don’t need to connect a battery to use Raspberry Pi, though, since it will automatically update its clock when turned on, so long as it has access to the internet.
At the bottom left of the board is a USB C power port, used to provide Raspberry Pi with power through a compatible USB C power supply. The USB C port is a common sight on smartphones, tablets, and other portable devices. While you could use a standard mobile charger to power your Raspberry Pi, for best results you should use the official Raspberry Pi USB-C Power Supply: it’s better at coping with the sudden changes in power requirements that can occur when your Raspberry Pi is working particularly hard.
At the left edge of the board is a small button facing outwards. This is Raspberry Pi 5’s new power button, used to safely shut down your Raspberry Pi when you’re finished with it. This button is not available on Raspberry Pi 4, or older boards.
Above the power button is another connector, which, at first glance, looks like a smaller version of the CSI and DSI connectors. This almost-familiar connector connects to Raspberry Pi’s PCI Express (PCIe) bus: a high-speed interface for add-on hardware like Solid State Disks (SSDs). To use the PCIe bus, you’ll need the Raspberry Pi PCIe HAT add-on to convert this compact connector to a more common M.2-standard PCIe slot. You don’t need the HAT to make full use of Raspberry Pi, though, so feel free to ignore this connector until you need it.
At the top edge of the board are 40 metal pins, split into two rows of 20 pins. These pins make up the GPIO (general-purpose input/output) header, an important feature of Raspberry Pi, that lets it talk to additional hardware from LEDs and buttons all the way to temperature sensors, joysticks, and pulse-rate monitors.
The final port on Raspberry Pi is on the underside of the board where you’ll find a microSD card connector positioned almost exactly underneath the top-side’s connector marked ‘PCIe’. This connector is for Raspberry Pi’s storage device: the microSD card inserted in here contains all the files you save, all the software you install, and the operating system that makes your Raspberry Pi run. It’s also possible to run your Raspberry Pi without a microSD card by loading its software over the network, from a USB drive, or from an M.2 SSD. For our purposes, we’ll keep it simple and focus on using a microSD card as the
main storage device.
