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Review by Tim Blythman Raspberry Pi 5 Originally designed as a cheap computer for use in education, Raspberry Pi single-board computers (SBCs) have been used in a vast range of applications. It’s just on five years since the release of the Raspberry Pi 4, and we finally managed to get a Raspberry Pi 5 to test and review. S ince 2012, we have seen the release of a new Raspberry Pi SBC (single-board computer) every year or so. However, there was quite a gap between the Raspberry Pi 4 and the Raspberry Pi 5, which wasn’t helped by the component shortages of the last few years. In 2021, the Raspberry Pi Foundation released the Pico microcontroller board, based on the RP2040 ARM microcontroller, followed by a Pico W variant with WiFi and Bluetooth capabilities. The inexpensive Picos have been embraced by the Arduino, Micropython and Micromite communities. We reviewed the Pico in December 2021 (siliconchip.au/Article/15125). siliconchip.com.au We have used it in numerous projects because of its low price and ease of use. The documentation for the Raspberry Pi Pico is written with the intention of using a Raspberry Pi computer as the development machine. With this in mind and many recent SBCs being touted as replacements for desktop machines, we’ll consider the Pi 5’s suitability for this task. 2021 also saw the release of the Raspberry Pi Zero 2 W, the most recent iteration of the compact Zero form factor SBCs and the first Zero with a 64-bit processor. It is based on the processor from early versions of the Raspberry Pi 3 but uses a system-in-­ package (SIP) known as the RP3A0. Australia's electronics magazine This combines the processor and RAM into the space-saving package needed to create a Zero board. The fact that the Raspberry Pi Foundation is now producing its own silicon (both for the Pi Zero 2 W and the Picos) is a notable advance. The Raspberry Pi 5 also includes an RP1 I/O controller, another of their products. We’ll delve into the RP1 and other Raspberry Pi 5 features shortly. The Pi 5 The Raspberry Pi 5 was released in September 2023, with the 4GB RAM variant being available first. There is also a version with 8GB of RAM. Interestingly, the Pi 5 drops the Model B July 2024  39 Table 1 – comparison between the ROCK 4C+, Raspberry Pi 4B & Pi 5 ROCK 4C Plus Raspberry Pi 4B Raspberry Pi 5 RockChip RK3399T (6 cores) Dual 1.5GHz ARM-Cortex A72 + Quad 1.0GHz ARM-Cortex A53 1MB + 512KB L2 caches BCM2711 (4 cores) Quad 1.8GHz ARM-Cortex A72 1MB L2 cache BCM2712 (4 cores) Quad 2.4GHz ARM-Cortex A76 512kB L2 cache per core 2M L3 shared cache Processor (CPU) 600MHz Mali T860MP4, four shaders, 256KB L2 cache 500MHz VideoCore 6, 1MB L2 cache shared with CPU cores 800MHz VideoCore 7, 2MB cache GPU two micro-HDMI, up to 4K + 2K (60Hz with one or both) two micro-HDMI, up to 4K + 4K (60Hz with one or 30Hz for both) 2 micro-HDMI, up to 4K+4K (60Hz with one or both) Display output HD stereo, up to 24bit/96kHz Stereo, PWM-based None Audio output 4GB 1GB, 2GB, 4GB or 8GB 4GB or 8GB RAM 5V/3A, USB-C or pin header 5V/3A, USB-C or pin header 5V/5A, USB-C or pin header Power req. 2× USB2, 2× USB3 2× USB2, 2× USB3 2× USB2, 2× USB3 USB 1× Gigabit 1× Gigabit 1× Gigabit Ethernet 802.11 b/g/n/ac (WiFi 5) Bluetooth 5.0 u.FL antenna 802.11 b/g/n/ac (WiFi 5) Bluetooth 5.0 PCB antenna 802.11 b/g/n/ac (WiFi 5) Bluetooth 5.0 PCB antenna Wireless 40-pin header: 1× PWM 2× SPI channels 2× I2C channels 1× ADC (analog) channel 40-pin header: 4× PWM 2× SPI channels 2× I2C channels 40-pin header: 4× PWM 2× SPI 2× I2C I/O suffix used for previous models. Given that there was no Model A for the Pi 4, it makes sense that the designations have been streamlined. We are reviewing the 4GB Pi 5 board. Table 1 shows a comparison between the Pi 4B, Pi 5 and the ROCK 4C+ SBC that we reviewed in April 2024 (siliconchip.au/Article/16210). The latter is roughly on par with the Pi 4B, although it includes a few nice features that the Pi 4B lacks. On the other hand, the Raspberry Pi machines have better software support and a larger community. Unsurprisingly, the newer Pi features a faster processor than the 4B. Most benchmarks indicate that the Pi 5 runs at least twice as fast as the Pi 4B. It is an ARM Cortex A76 in the form of a Broadcom BCM2712, which implements the ARMv8.2-A 64-bit instruction set. Not only is the processor faster, but the microSD card interface on the Pi 5 is capable of running twice as fast as that on the Pi 4B, and the Ethernet interface also transfers data faster. The GPU in the Pi 5 can also drive two 4K displays at 60Hz, compared to the Pi 4B, which can only drive one 4K display at 60Hz. The main compromises are the power and cooling requirements, with 40 Silicon Chip the Pi 5 now specifying a 5V 5A (25W) supply over the Pi 4B’s 5V 3A (15W) supply. Our Pi 5 happily booted up with the 3A supply we had been using for our Pi 4B and ROCK 4C+, although it showed a message that ‘power to the peripherals will be restricted.’ Screen 1 shows the initial desktop with this message. An official 27W Raspberry Pi power supply offers USB-C PD (power delivery), including 9V, 12V and 15V output voltages. Curiously, the output specified for use with the Pi 5 is 5.1V. Hardware Photos 1 & 2 are close-ups of the front and back of the Pi 5 with various features marked out. The overall layout is much the same as earlier models, although it is different enough that it will not fit in cases designed for earlier models. There is little of interest on the back except the microSD card socket. The main layout difference from the Pi 4B is the transposition of the USB and Ethernet connectors. The mounting holes and GPIO headers are in the same locations, and the other main external features are in much the same, if not identical, positions. Like the Pi 4B, the USB connector for power input is a USB-C type, and adjacent are two micro-HDMI (HDMI Australia's electronics magazine type D) sockets to allow dual monitor connections. The Pi 3B and earlier models have a single full-size HDMI socket and one micro-USB socket. You’ll need a cable with a microHDMI plug rather than an adaptor to use both HDMI sockets since the adaptor will likely foul the USB-C socket. Our basic single-monitor setup worked using the HDMI socket (with an adaptor), HDMI1, further from the USB-C socket. The top of the Pi 5 looks quite sparse; many of the passive components are on the back of the board. The main processor is the larger chip with a metal shield (we attached an aluminium finned heatsink to it, visible in the photos); the rectangular chip next to it is the RAM. The second shielded package is the radio module, providing WiFi and Bluetooth connectivity. The RP1 ‘southbridge’ I/O controller is the large chip with the Raspberry Pi logo near the USB sockets. This is one of the ICs the Raspberry Pi Foundation has designed and produced. The RP1 connects to the processor via a fourlane PCIe 2.0 interface. Bundling many of the I/O functions into a single chip allows substantial performance improvements for the Pi 5 over the Pi 4B. The RP1 even handles GPIO functions on the 40-pin header siliconchip.com.au GPIO Header RAM Chip RP1 Chip Fan Connector WiFi Module 2x USB2 PCB Antenna ARM Processor 2x USB3 PCIe Power Switch Status LED Ethernet USB-C (Power) PoE HAT Header RTC Battery 2x HDMI Composite Video 2x MIPI CSI/DSI Connector Photo 1: the Raspberry Pi 5 is the same size and shape as its predecessors, but the connectors have been slightly rearranged, so it requires a different case. The official case includes a small fan that provides much-needed cooling. The same GPIO pinout applies as the previous Pis, so most existing HATs should work with the latest Pi. The supplied RAM is indicated with a component fitted to the MEMORY box. and has been designed to provide the same I/O functions as the Pi 4B. The RP1 provides Gigabit Ethernet, two USB 3 interfaces, two USB 2 interfaces and two MIPI transceivers for cameras/displays on the J3 and J4 CSI/DSI connectors. The RP1 also includes the versatile PIO (programmable input-output) peripheral and an ADC (analog-to-digital converter). These latter two features are not used on the Pi 5. The RP1 relieves the main processor of most of the peripheral duties. There is more information on the RP1 at siliconchip.au/link/abvc The Pi 5 dispenses with the 3.5mm TRRS socket used for audio and composite video in earlier versions. Instead, video is available from a dedicated two-pin header (marked as VID next to HDMI1). Two of the GPIO pins on the 40-pin header can produce PWM-based audio, although this does not appear to be enabled by default. The top of the board also has a four-pin PoE (Power-over-Ethernet) header for connecting to a PoE HAT. HAT (hardware attached on top) is the Raspberry Pi terminology for a shield or daughterboard. The top of the Pi 5 also breaks out a four-pin polarised header (J17) for a fan. An active cooler is available to siliconchip.com.au suit the Pi 5, which can connect to J17. The active cooler mounts to two holes adjacent to the four main mounting holes. The official case for the Pi 5 also incorporates a fan that can be powered from J17. A three-pin polarised header (J16), labelled UART, can be used for diagnostics. The Renesas DA9091 PMIC (power management integrated circuit) is near the USB-C socket. It incorporates a real-time clock (RTC) feature that utilises an optional battery connected to the nearby J5 polarised header. The two-pin header pads marked J2 next to J5 are connected in parallel with a momentary pushbutton (marked PSW) used as a power switch. It is adjacent to a bicolour LED labelled STAT. J20 is a flexible flat cable (FFC) connector marked as PCIe that breaks out a single PCI Express 2.0 lane. It is Photo 2: the underside of the Pi 5 is populated mainly by passive components. Australia's electronics magazine July 2024  41 expected that future HAT designs will use this interface, and it is suggested that this will be most commonly used for connecting an NVMe solid-state drive (SSD) for storage. The back of the board is mainly populated with passive components and the microSD card socket that holds the operating system. There are also options to configure a boot EEPROM to allow booting from a USB storage device or an NVMe SSD. Setting it up Like just about every other SBC, the Pi 5 typically uses a microSD card for the operating system and user files. Hence, installation involves transferring a disk image to the card using another computer. The Raspberry Pi Foundation provides the Raspberry Pi OS, which is based on Debian Linux. Operating system downloads can be found at siliconchip.au/link/abvd and that page indicates which versions are compatible with which Pi boards. There are bundles pre-loaded with different programs. We used the latest version (v5.2, March 2024), which includes all the recommended software. This download comes to around 3GB and expands to a 15GB file. A 32GB card is recommended. We previously used WinDiskImageWriter to transfer the image files to the microSD card, but this time, we tried Raspberry Pi Imager, which has been available since 2020. This, as well as other software, can be downloaded from www. raspberrypi.com/software Screen 2 shows the Imager program. It can automatically download card images as well as write previously downloaded files. Imager can also configure the image with settings like WiFi, country and SSH, allowing the Pi to operate in headless mode (without a keyboard, mouse or monitor). Writing the file and verifying the image took about half an hour; the verification is a nice touch. The Imager is a good way to see what other software is available. It lists media player and emulation images, among others. Even if you don’t have a Pi, we suggest downloading Imager to see what other people are doing with their Pi. Once the image is transferred, the Pi 5 is booted by installing the card, connecting the monitor, keyboard, and mouse, then plugging in the power supply. The first boot sets up a few things and performs a system update. Once everything was set up and the update completed, the Pi 5 responded quickly. A reboot took about 15 seconds, comparable to modern computers fitted with SSDs. Using it The Raspberry Pi Foundation does a good job of making their software easy to use; the mix is much the same as earlier distributions. Educational programs like Scratch, Mathematica and Wolfram are included, as is Thonny (an integrated development environment [IDE] for the Python programming language). All these programs would be familiar to seasoned Pi users. We then looked for programs that would be useful in a typical office environment. The LibreOffice suite (including word processor and spreadsheet) was installed, as were the Chromium and Firefox web browsers. Many of the included programs may not be familiar if you have previously only used Windows or macOS. However, they will be known to those familiar with open-source alternatives to proprietary programs. Even the open-source KiCad EDA (electronics design automation) suite is installed. The Arduino IDE is not installed by default, but it and many others can be added through the Preferences → Add/Remove Programs dialog box. Using the Arduino IDE on the Pi 5 was practically the same as on the Windows machines we are used to. Some programs we use, like Altium Designer, are only available for Windows operating systems. Although the MPLAB X IDE is available for Linux (and Raspberry Pi OS is a Linux variant), currently, it only works on x86 and x64 processors and not ARM processors. We were able to program a Pico from the Pi 5 from a command line interface with relative ease. So, a good proportion (but not all) of the programs we use daily are available or easy enough to install on the Pi 5. ARM processors are becoming more common on portable and desktop computers, such as M2-based Mac computers or Microsoft Surface devices with an SQ2 processor. We expect support for ARM processors to grow steadily; hopefully, that will translate to better software options for computers like the Raspberry Pi. Screen 1: the initial desktop after setting up the Pi 5; it looks much the same as previous versions. The messages at top right indicate that it has connected to a preconfigured WiFi network and that the connected power supply cannot provide the 5A needed for full functionality. 42 Silicon Chip Australia's electronics magazine siliconchip.com.au Still, the appearance and functionality are similar. The Desktop software lacks broad hardware support, so we couldn’t fully use the PC’s features. In particular, WiFi would not work, so we had to devise an alternative way to connect to the internet using a USB dongle. If you have an old PC, Raspberry Pi Desktop could be an easy way to try out the Raspberry Pi OS. Be aware that the flash drive and your PC’s hard drive could be erased if you do that. Conclusion Screen 2: the Raspberry Pi Imager is a helpful tool for setting up the microSD card and seeing what other disk images are available. Initially, we ran this on a Windows computer but it comes preinstalled on the Pi. The performance of the Pi 5 was generally quite good, and the system seemed responsive. The processor gets very hot, though; too hot to touch, so one of the cooling options would be beneficial. Raspberry Pi Desktop An interesting footnote we found on the www.raspberrypi.com/­software/ operating-systems page is Raspberry Pi Desktop. It’s an operating system image for PC and Mac computers (those with x86 or x64 processors) that provides a Linux environment similar to that found on the Raspberry Pi boards. We loaded this onto a USB flash drive with the Rufus program (https:// rufus.ie/en/), a utility that can be used to create bootable flash drives. We plugged the drive into an older PC and booted it up. The flash drive can install the Raspberry Pi Desktop operating system to the hard drive (so you don’t need to boot from the flash drive). Alternatively, you can run it directly from the flash drive. Screen 3 shows the desktop environment and program installation. The Raspberry Pi Desktop is based on Debian 11, an older version than the Debian 12 used in current versions of Raspberry Pi OS (for the Pi SBCs). With ARM chips gaining a foothold in the market traditionally held by x86 and x64 processors, software availability for computers like the Raspberry Pi can only grow. The Raspberry Pi Foundation is now producing some of its own chips; that’s a promising sign, and we look forward to their future developments. While it’s still no match for most PCs, the Raspberry Pi 5 works well enough to do many of the daily tasks that the average person needs. Various programs are still unavailable for ARM Linux, so a Windows PC will remain our tool of choice for the foreseeable future. Still, the Pi 5 makes a great second machine and is well-priced as an educational computer for children. It’s also an excellent way to try out Linux if you haven’t done so already. The Raspberry Pi 5 and its accessories are available from Altronics (Z6302J for the 4GB version and Z6302K for the 8GB version), as well SC as Mouser and DigiKey. Screen 3: Raspberry Pi Desktop is a version of the Raspberry Pi OS for x86 and x64 computers. It is a good way to try out the Raspberry Pi environment, although the hardware support is not as good as on the Pi boards (or your average PC Linux distribution). The latest version of Raspberry Pi Desktop is also a couple of years old now. siliconchip.com.au Australia's electronics magazine July 2024  43