The Raspberry Pi Pico...and a Tiny Plug-In Pi
Yesterday the Raspberry Pi Foundation announced the Raspberry Pi Pico, at the boggling temporary low price of...$4US. It's definitely a microcontroller on the order of an Arduino rather than the high-end 8GB RPi that might stand in for a complete desktop mobo. And that's ok by me. The chip at its heart is new: the RP2040, a single-chip microcontroller designed to interface with mainstream Raspberry Pi boards, and lots of other things.
Now, what caught my attention in the page linked above was the list of partner products made by other firms using the same RP2040 chip. Scroll down to the description of the SparkFun MicroMod RP2040 proccesor board. It's still on preorder, but look close and see what's there: an edge connector...on a board the size of a quarter! That's not precisely what I was wishing for in my previous entry, but it's certainly the right idea.
As I understand it, SparkFun is turning the RPi-wearing-a-hat on its ear, into a hat-wearing-an-RPi. The M.2 interface used in the product is actually a standard developed some years back for use in connecting SSDs to tiny slots on mobos. I knew about M.2, but wouldn't have assumed you could mount a CPU-add-in board using it. Well, shazam! Done deal.
The RP2040 chip is a little sparse for my tastes. I want something I can run FreePascal/Lazarus on, over a real OS. I don't see anything in the M.2 spec that would prevent a much more powerful processor board talking to a device (like a keyboard, TV or monitor) across M.2. The big problem with building a high-end RPi into things is keeeping it cool. The Foundation is aware of this, and did a very good job in the $100US Raspberry Pi 400 Pi-in-a-keyboard. (This teardown and review is worth a look if you're interested in the platform at all. The author of the teardown goosed the board to 2.147 GHz and it didn't cook itself.)
I fully intend to get an RPi 400, though I've been waiting awhile to see if there will soon be an RPi 800 keyboard combo with an 8GB board instead of 4GB. Given the price, well hell, I might as well get the 4GB unit until an 8GB unit appears.
So consider my previous post overruled. It's already been done. And I for one am going to watch this part of the RPi aftermarket very carefully!