Five reasons to build a custom IoT chip – as directed by Arm
In a serious-minded classroom setting at Electronica 2018 earlier this month, up in the gods at Munich Messe, UK-based chip design company Arm presented to a handful of enthusiasts about the virtues of custom (system-on) chips for industrial IoT products.
Enterprise IoT Insights was among its pupils for the 40 minute session. In a series of posts, we will re-present, re-purpose, quote, and paraphrase, in order to share its advice for the IoT developer community.
Alessandro Grande, developer advocate at Arm, played teacher in Munich. He considered the trends in the technology market, the reasons for developers to specify a system-on-chip (SoC), and how they might go about building it.
The first post in the series deals with Grande’s initial observations, only; a flurry will follow to discuss the practicalities of design and construction.
So, some context, to start…
Grande’s position is the same as his employers’; neither has built a chip for a product, and yet they are experts on chip design. Arm is in the business of blueprints, and Grande is a point man for developers interested in them.
“We provide the building blocks to build chips,” he explains in Munich. Arm’s ‘ecosystem partners’ shipped 17 billion chips in 2017, and its volumes are spiralling upwards with the enhancement and multiplication of connected ‘things’ in homes and work places.
The mad growth statistics hardly need mentioning, but Grande cites a couple: Gartner predicts 500 new smart devices in every home by 2022; BCG anticipates 12 million fully autonomous vehicles will be shipped annually by 2025.
Developers can choose to build with off-the-shelf components, loading a printed circuit board (PCB) with the most appropriate and commonly available electronic parts. But there is an alternative way: to specify optimised devices that deliver better performance.
But why go through the pain of designing a chip from scratch, when there are tried and trusted components readily available? Here are five reasons for developers to embrace the challenge of a custom SoC.
Every computing revolution starts with silicon. As chip performance jumps each year, process nodes become more optimised, and the cost of building on the better established ones goes down. Today, you can build a test chip for a few hundred thousand dollars.
“When I was in university, we used to talk about how to build a custom chip, it would take you millions. This has completely changed now,” says Grande.
A 180 nm test chip, standard for mixed signal SoCs, will set you back around $20,000, he suggests; a 65 nm design, of the kind that powered the first smartphone devices, can be built for less than $50,000. A custom SoC is eminently viable.
But the reason to embark upon a bespoke design project is to achieve higher performance. The final product, out of a custom design, achieves an elegance that cannot be matched by stitching catalogue components together on a PCB.
“By moving to a one-chip solution, you reduce the number of components and, therefore, you reduce the complexity of the system,” explains Grande.
In turn, he says, you reduce the size of the whole system, and enable products with a smaller footprint – which ultimately begets more attractive product designs, and possibly new use cases.
This reduced complexity also impacts the supply chain, which is squeezed like an accordion until the fabrication works on a single component at a single site. Control is tightened, and reliability improves.
“You’re not depending on a lot of different vendors for lots of different bits; you’re just depending on your own silicon, from your own foundry or design house,” says Grande.
The test design will require fewer re-spins, as well, just because it is more challenging to reverse-engineer a system based off discrete components, than off a single piece of silicon.
In the end, an IoT product based on a custom SoC is more than just fit-for-purpose; it is engineered for one purpose only, and should benefit from its singular focus.
“You can now optimise the performance and power consumption of the chip because you have full control over the whole system,” explains Grande.
S3 Semiconductors, an Arm partner, worked with a customer to develop its own chip, replacing a PCB solution with a single piece of silicon; the bill-of-materials reduced by 80 per cent, says Grande.
Control over the design brings control over both the budget and the performance; developers are not hostage to the pricing and compromise of available parts. In the S3 example, power consumption was reduced by 70 per cent and the size of the system was reduced by 75 per cent.
More than this, the flexibility afforded by a more sparing chip design created opportunities to add new functionality, and drive new business.
“Because they were now in control of the whole chip, they managed to differentiate their solution and add connectivity, which allowed them to open up a whole new business stream,” explains Grande.
Five reasons for developers to build a custom IoT chip – as signed by Arm
Six steps for developers to build a custom IoT chip – as signed by Arm (Pt 1)
Six steps for developers to build a custom IoT chip – as signed by Arm (Pt 2)