Raspberry Pi 4 has been revealed, as a far more powerful machine than even the Pi 3 Model B+. Three times the processing power and four times the multimedia performance are claimed.

It has quad 1.5GHz Arm Cortex-A72 cores, Gbit Ethernet, 4Kp60 HEVC video decode and dual HDMI outputs to run twin 4K monitors – many of the changes have been made to improve consumer and industrial performance, without compromising its original educational role.

1, 2 and 4Gbyte variants (using LPDDR4) will be offered, with prices starting at the traditional $35, and the board size remains the same.

Looking at the specs, the Raspberry Pi 4 main chip, to be called BCM2711, has had significant changes to its peripherals as well as its core – something that hasn’t happened between earlier generations.

“It’s a pretty fundamental shake-up” Raspberry Pi Trading CEO Eben Upton told Electronics Weekly. “We’ve overhauled every aspect of the design, from the CPU and memory, to the multimedia, display output and non-multimedia IO.”

Why the move from Cortex-A53 to A72?

“Cortex-A53 represents pretty much the limit of what you can achieve with an in-order core – A55 reportedly gives you another 10%, but nothing earth-shattering, so to get a significant performance uplift you’d either need to go to an incredible clock speed, say in the 3GHz range, or use one of the ‘large’ A7x out-of-order cores,” said Upton, who was closely involved in the architectural design of the new SoC.

Where has all the extra video performance come from – maybe Broadcom’s VideoCore V?

“This has a Broadcom VideoCore VI in it – the evolved version of VideoCore V that supports newer standards like OpenGL ES 3.2,” said Upton. “This is roughly another decade of continuous development on top of the VideoCore IV platform we used in previous products.”

Serial IO

Serial IO on the BCM2711 is far better than on earlier Pi chips.

For example, Ethernet speed used to be hampered because its connection to the main SoC had to be through an on-PCB USB port. On the Pi 4, Broadcom’s BCM54213 Gigabit Ethernet PHY has appeared, connected at full bandwidth to a MAC on the BCM2711 via a dedicated RGMII interface.

On-board wireless connections remain Wi-Fi 802.11ac and Bluetooth, although Bluetooth is now 5.0, up from 4.2.

For the first time on a Pi, two USB 3 connectors have appeared, attached to the main SoC via a single lane of PCI Express – so the total user port count is now two USB 2 and two USB 3.

Alongside this on the chip are four additional PL011 UARTs, four new SPI and four new I2C interfaces.

What has not been added is dedicated hardware support for virtualisation. “I expect that users interested in running multiple isolated virtual machine images on the device would end up using a para-virtualisation approach,” said Upton.

Some Raspberry Pi 3B+ users running sustained high processing loads across all four cores found it necessary to add a heatsink, a fan, or both to the SoC. Will Raspberry Pi 4 need a fan?

“It will benefit from a fan and/or heatsink if you want to run it flat-out for extended periods,” said Upton, “but it’s been designed to meet most user requirements – web browsing, document editing, software development, video – without throttling and without an additional thermal solution.”

The power plug is now USB-C, and the official power supply is now a 3A (5V) unit, although the existing 2.5A PSU is said to be usable “if you don’t need a full 3 amps”, according to the foundation, and it has made a $1 micro USB to USB-C adaptor available.

Industrial use

Alongside traditional educational use, more serious consumer, industrial and commercial uses are foreseen for Pi 4.

“Just as we help make coding more accessible for consumers, we also aim to democratise digital innovation in businesses and public services,” said Upton, “Today, over 50% of our $35 Raspberry Pi units are destined for industrial and commercial use. Raspberry Pi 4 builds on this, providing greatly increased performance at the same cost. We aim to provide a low-cost platform for technological innovation that is accessible to every organisation, from start-ups to multinationals.”

A Raspberry Pi 4 can serve both as an embedded controller and as a full-featured Linux workstation, according to Raspberry Pi: “For the first time it will be possible to both develop and deploy industrial IoT applications on a single common hardware platform.” With Gigabit Ethernet, 802.11ac, Bluetooth and more serial ports “it can serve as a leaf node in an IoT network, or as a data aggregator for a large network of sensors.”

Updated video performance also suits Pi 4 to dual screen digital signage and high-end thin client use.

“Bringing PC-equivalent performance to the sub-$50 price bracket, Raspberry Pi 4 is the natural choice for developing and deploying industrial IoT applications; and monitoring and control of a broad range of industrial equipment.” said Raspberry Pi, adding that “as with all Raspberry Pi products, a high level of backward compatibility facilitates migration” of existing Pi applications.

Consumer use

With dual-screen 4K-capability and up to 4Gbyte of ram, Rasberry Pi is describing Raspberry Pi 4 as “a complete desktop computer, and the world’s most affordable multimedia PC. For the first time, it replicates the full range of capabilities of a traditional PC – from super-fast file sharing to multi-tab web browsing and sophisticated video and photo editing – all in a tiny, eco-friendly, ethically-produced package.”

“The vision behind Raspberry Pi 4 is to make a rich multimedia PC experience accessible to everyone. By offering a ‘just right’ level of performance for most users, we’ve been able to do this at roughly a tenth the cost of a traditional desktop PC” said Upton., adding: “Raspberry Pi is already the best-selling British computer of all time. In 2018 Q4 Raspberry Pi 3+ and earlier models accounted for 2.5% of the global PC market; the improved capabilities of Raspberry Pi 4 should allow us to address a much larger fraction of that market.”

Hobbyist and maker communities get access to Gigabit Ethernet and USB 3.0 connectivity. “As with all Raspberry Pi models, Raspberry Pi 4 is designed to be backwards-compatible, so that old creations will for the most part work without modification on the new device,” according to Raspberry Pi.

For programming, Raspberry Pi 4 comes with a range of programming languages, from Scratch to Python and C++.

Later today, Raspberry Pi 4 will be available from element14 and Okdo (part of RS), as well as the global network of approved resellers and from the physical Raspberry Pi store in Cambridge UK – in the Grand Arcade shopping centre.

There is an optional Desktop Kit, bundling a Raspberry Pi 4 with a mouse, keyboard, SD card, power supply, cables and case – everything needed except a monitor.

For more technical information, the Raspberry Pi Foundation blog now has Pi 4 as its top story.

By: DocMemory
Copyright © 2023 CST, Inc. All Rights Reserved