Since Raspberry Pi was going so far as to make their own silicon, they definitely could have opted to include a RISC-V design instead of an ARM design. They simply chose not to.
RISC-V would have made this product an instant buy in my books, but there are numerous Cortex-M0+-based microcontrollers and microcontroller boards out there already.
The Pi Pico is appealing because of all the documentation and the ecosystem that is sure to develop around it, so I'm not here to claim that this product won't be wildly succesful, but the M0+ is just not the choice I would have expected them to make. RISC-V seems like it would have aligned much better with the Raspberry Pi Foundation's mission.
In fact, if they had chosen to integrate the ESP32-C3 into this product instead of their custom silicon, people would be receiving RISC-V, WiFi, and Bluetooth -- and you can imagine how beneficial that would be. The ESP32-C3 is supposed to cost around $1, so it's not like it would have been outrageously expensive or something.
I do recognise what you say about there being a choice. But this project was surely years in the making and the tech had to be available back then. This isn't a huge company. This is a charity's first attempt at creating a low-cost microcontroller with first class documentation and support. And considering Upton's ARM background I think the ARM choice is the obvious one.
Your point about the ecosystem and the documentation is important here, this is extremely valuable considering their mission and simply would not have existed at the same quality level if using some brand-new ESP chip - is it even available to buy anywhere yet (I can't find a seller)? And if you haven't had a look at the RP2040 datasheet[0] yet, please do - it is really something with multiple real-life examples and hints that goes a long way beyond what you usually get. If they had built something around the C3 it'd be a long while before anything near the same level could be created and in the hands of kids. They want an established ecosystem to build on, not a cutting edge one. I do not think it's a good fit (yet).
Your comment is predicated on the assumption that they couldn't have worked with the other RISC-V design teams in this space for the past few years -- that they would have had to wait until products hit the shelves in order to start, which is simply not true. They could have started design collaboration with others whenever they started this project, and they would have almost certainly ended up where they are now today, except with RISC-V.
Most likely, the real issue is that it would have required them to make a really visionary choice, which does come with a significant level of risk. Hindsight is 20-20, and with perfect clarity we can see now that that RISC-V ecosystem has matured extremely quickly and is now a very compelling place to be. There is a ton of stuff in RISC-V -- it's not some void as you seem to be implying.
Instead, when they set out on this project, they chose to lean on their own internal strengths, which is certainly the ARM architecture. Back then, I'm sure things were less obvious than they are now -- but that's why I want them to do visionary things to move industry and education forward.
Espressif (the makers of ESP32) don't seem to be in nearly as comfortable of a position to try innovative things as the Raspberry Pi Foundation is, yet they managed to release a compelling RISC-V option -- because that industry trend was obvious enough to them, I guess, even if it wasn't obvious enough to the Raspberry Pi Foundation.
As I've indicated, I'm sure this product will be successful, and I'm excited to see what people do with this, but I can still wish the Pi Foundation would have done something more here. I'm not wishing them failure or anything like that at all.
None of us know what was available back then but you are right, maybe there was an option to work with someone and maybe even with results in a similar time frame. But considering the greater risk I don't think there is certainty how a collaboration with an external partner on a new technology would have ended. I am also not convinced we need RISC-V to move education forward meaningfully and I think what they've got here will do the job.
Hopefully people will be able to buy something similar based on RISC-V for <£5 soon and that'll kick-start even more options in this space. But we don't seem to be there quite yet.
To provide just two quick examples:
- https://www.sparkfun.com/products/15594
- https://www.cnx-software.com/2020/12/20/esp32-c3-wifi-ble-ri...
Since Raspberry Pi was going so far as to make their own silicon, they definitely could have opted to include a RISC-V design instead of an ARM design. They simply chose not to.
RISC-V would have made this product an instant buy in my books, but there are numerous Cortex-M0+-based microcontrollers and microcontroller boards out there already.
The Pi Pico is appealing because of all the documentation and the ecosystem that is sure to develop around it, so I'm not here to claim that this product won't be wildly succesful, but the M0+ is just not the choice I would have expected them to make. RISC-V seems like it would have aligned much better with the Raspberry Pi Foundation's mission.
In fact, if they had chosen to integrate the ESP32-C3 into this product instead of their custom silicon, people would be receiving RISC-V, WiFi, and Bluetooth -- and you can imagine how beneficial that would be. The ESP32-C3 is supposed to cost around $1, so it's not like it would have been outrageously expensive or something.