In the latest issue of The MagPi Magazine, on sale now, Gareth Halfacree asks what goes into making Raspberry Pi’s first in-house microcontroller and development board.
“It’s a flexible product and platform,” says Nick Francis, Senior Engineering Manager at Raspberry Pi, when discussing the work the Application-Specific Integrated Circuit (ASIC) team put into designing RP2040, the microcontroller at the heart of Raspberry Pi Pico.
It would have been easy to have said, well, let’s do a purely educational microcontroller “quite low-level, quite limited performance,” he tells us. “But we’ve done the high-performance thing without forgetting about making it easy to use for beginners. To do that at this price point is really good.”
“I think we’ve done a pretty good job,” agrees James Adams, Chief Operating Officer at Raspberry Pi. “We’ve obviously tossed around a lot of different ideas about what we could include along the way, and we’ve iterated quite a lot and got down to a good set of features.”
A board and chip
“The idea is it’s [Pico] a component in itself,” says James. “The intent was to expose as many of the I/O (input/output) pins for users as possible, and expose them in the DIP-like (Dual Inline Package) form factor, so you can use Raspberry Pi Pico as you might use an old 40-pin DIP chip. Now, Pico is 2.54 millimetres or 0.1 inch pitch wider than a ‘standard’ 40-pin DIP, so not exactly the same, but still very similar.
“After the first prototype, I changed the pins to be castellated so you can solder it down as a module, without needing to put any headers in. Which is, yes, another nod to using it as a component.”
Getting the price right
“One of the things that we’re very excited about is the price,” says James. “We’re able to make these available cheap as chips – for less than the price of a cup of coffee.”
“It’s extremely low-cost,” Nick agrees. “One of the driving requirements right at the start was to build a very low-cost chip, but which also had good performance. Typically, you’d expect a microcontroller with this specification to be more expensive, or one at this price to have a lower specification. We tried to push the performance and keep the cost down.”
Raspberry Pi Pico also fits nicely into the Raspberry Pi ecosystem: “Most people are doing a lot of the software development for this, the SDK (software development kit) and all the rest of it, on Raspberry Pi 4 or Raspberry Pi 400,” James explains. “That’s our primary platform of choice. Of course, we’ll make it work on everything else as well. I would hope that it will be as easy to use as any other microcontroller platform out there.”
Eben Upton on RP2040
“RP2040 is an exciting development for Raspberry Pi because it’s Raspberry Pi people making silicon,” says Eben Upton, CEO and co-founder of Raspberry Pi. “I don’t think other people bring their A-game to making microcontrollers; this team really brought its A-game. I think it’s just beautiful.
“What does Raspberry Pi do? Well, we make products which are high performance, which are cost-effective, and which are implemented with insanely high levels of engineering attention to detail – and this is that. This is that ethos, in the microcontroller space. And that couldn’t have been done with anyone else’s silicon.”
Issue #102 of The MagPi Magazine is out NOW
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