Thumby / RPi RP2040 specs

[rubinstu]

I have some questions about the Thumby system specs.  In addition to the specs in https://www.kickstarter.com/projects/kenburns/thumby-the-tiny-playable-keychain and https://www.arm.com/blogs/blueprint/raspberry-pi-rp2040:

What is the boot medium? Flash? Is this on-board or an exernal flash?

How much RAM is onboard the RP2040? I assume there is no external RAM, is that true?

The spec says "Memory: 2MB total storage". How is this broken down?

Is there any  crpyto acceleration hardware on the RP2040?

Thanks!

[Ben Rose]

Hi- the 2MB flash is a QSPI flash chip, the same one as used on the Raspberry Pi Pico. By default we plan to have the standard Pi Pico MicroPython interpreter loaded, which I believe is about half a MB, leaving about 1-1.5MB available.

There's 264KB RAM, no crpyto acceleration hardware that I'm aware of. Full specs at:

https://datasheets.raspberrypi.org/rp2040/rp2040-datasheet.pdf

Thanks for the interest!
Ben

[RyanC]

Hi Ben,

Just a quick follow up to this question. Will there be any programs running in the background which will use up any of the limited 264Kb of RAM (such as a general menu manager to control loading/unloading of games)? If there is, how much memory will it take up? Asking as want to make sure any programs fit within the expected memory footprint.

Kieron

[Ben Rose]

Hi Kieron,

With how we plan to ship Thumby, the MicroPython interpreter will eat plenty of RAM as well as possibly some minimal assets leftover in memory from the main menu, however the menu essentially runs and then completely exits to the game(power off/soft reset to get back to the menu, for now).  I don't currently have a number for what's used- I've read things like 16-32KB for the interpreter. Let me know if you need a better answer.

I'll admit that during development of our little game examples, we haven't worried about memory, it's a lot more than we're used to!

Thanks,
Ben

[RyanC]

Thanks Ben,

I'd planned to keep RAM usage under 200kb, leaving 64kb as a safety margin so that pretty much answers my question. That was useful information about the menu system too.

Kieron

[rubinstu]

Ben, thanks for the info.