By One of the most exciting aspects of the Raspberry Pi 5 is the inclusion of a custom I/O controller chip. It may seem like a small detail, but when you look deep down you will realize that it can mean large changes coming.
The Raspberry Pi foundation has always been leveraging Broadcom SoCs for their designs. Developing an SoC is a huge undertaking, and a small company or foundation will not likely do so without huge and practically guaranteed returns. It makes sense for large semiconductor vendors.
But a custom IC is exactly that – custom. Built to specifications. While Broadcom may take some heed from RPI given their volume, large volume customers are their main targets.
With the Raspberry Pi 5, there was a realization that the I/O options being offered were not enough. It only made sense to have fast I/O connectivity to match an equally fast processor.
Even more, the Raspberry Pi platform has some unique requirements as mentioned by , like the ESD protection of the parts – RPIs are manipulated by hand pretty often. Suceptibility to ESD (from walking on a carpet, for example) would be a huge problem.
The RP1 solved the I/O problem, but it came at a large cost. Millions of dollars in effort. That’s a large commitment.
With the development of the RP1 I/O chipset, the Foundation has taken a significant step in custom silicon design. And the question is, where will this go? Now that the Raspberry Pi foundation has developed RP1 and also the RP2 (officially the RP2040 microcontroller), it’s clear they have the capability of creating chipsets, those targeted towards their end users which are both industrial customers as well as makers and hobyists.
Custom IC design is both an art and science, and getting a chip taped out (ready for production) is no small feat. This capability now helps differentiate Raspberry Pi from other SBC vendors in unique ways.
The RP1 I/O chipset represents the Raspberry Pi Foundation’s commitment to enhancing the performance and capabilities of their SBCs. The objective was to create a custom I/O controller that could handle various peripheral interfaces more efficiently than off-the-shelf solutions.
Development Process
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Identifying the Need: As Raspberry Pi SBCs grew in popularity, the need for a more robust and efficient I/O solution became apparent. Existing chips were either too expensive or lacked the integration required for the diverse applications of Raspberry Pi users.
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Design and Collaboration: The Foundation embarked on designing the RP1 with a focus on maximizing functionality while keeping costs low. Collaborating with chip design experts and leveraging their own in-house expertise, they created a chip tailored to their specific needs.
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Integration and Testing: Integrating the RP1 into the Raspberry Pi architecture involved rigorous testing to ensure compatibility and performance. Extensive validation processes were undertaken to ensure that the RP1 could handle various I/O tasks seamlessly.
Features of the RP1 I/O Chipset
- Peripheral Support: The RP1 is designed to support a wide range of peripherals, including USB, Ethernet, and GPIO.
- Efficiency: The custom design ensures lower power consumption and improved performance compared to generic I/O controllers.
- Cost-Effectiveness: By designing their own chip, the Raspberry Pi Foundation could better control production costs, passing savings onto consumers.
The introduction of the RP1 I/O chipset has significantly enhanced the Raspberry Pi’s capabilities, particularly in handling multiple peripherals simultaneously. This has expanded the potential applications of Raspberry Pi boards, making them more versatile for both educational and industrial uses.
From an industry perspective, it’s hard to see how this doesn’t start somewhat of an arms race. It may make sense to get your chipset vendor (Allwinner, TI, etc) to provide these features at a lower cost to compete, if your volume is enough to justify it.
The Raspberry Pi foundation isn’t the first. There’s been somewhat of a trend in the industry of creating custom chips to enhance performance, provide new features, and reduce cost and power consumption. A few examples are:
- Apple: Apple’s M1, M2 and M3 chips are custom designed to optimize performance and power efficiency for their Mac and iPad products, with amazing results
- Google: Google’s Tensor Processing Units (TPUs) are specialized for machine learning tasks, providing significant performance improvements over generic processors.
- Amazon: AWS Graviton processors are tailored for cloud workloads, offering cost and performance benefits for Amazon Web Services.
As technology advances, the trend towards custom chip design is expected to accelerate. Innovations in chip manufacturing, such as advanced process nodes and modular design techniques, will further facilitate this shift as slightly older nodes become cheaper. Companies will continue to invest in custom silicon to stay competitive and meet the specific needs of their users, and SBC manufacturers may need to look at opportunities to fulfill customer needs with custom silicon.