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Fast/modern platforms that allow "bare-metal" style coding?

category: code [glöplog]
...sorry, skip the "new" ;-)
added on the 2020-07-17 14:15:55 by Kuemmel Kuemmel
Sdw you should check out dreamcast development.

There‘s a nice SDK (KallistiOS), great emulators for testing/development and most importantly you get low-level access to the PowerVR GPU.

Also, Xbox Classic is a great underused platform with lots of potential. Did some demostuff on it myself (unreleased so far), it is a great system.
added on the 2020-07-18 16:14:57 by spike spike
Too bad my Pandora was never delivered because some British person(s) took the money to cover their own losses and was never heard from again. When writing the Germans the reply was "your business is with the British" except I never chose who to deal with. Well, you can't go through life without some scars.
added on the 2020-07-18 17:21:35 by El Topo El Topo
Perhaps something along these lines: https://www.clockworkpi.com/

Possibly modern mobile maybe, though the stack there is quite deep I suppose. Need to do a lot to get access to the bare-metal.

the closest you can get to baremetal is actually make the metal yourself: https://store.digilentinc.com/fpga-development-boards-kits-from-digilent/

You could also go for this? https://play.date/
added on the 2020-07-27 16:11:37 by oni_ oni_
Wow! Long time since I was here; but there's a post right in my current interest! :) I totally get Sdw's reasons for wanting to go bare metal. I feel very much the same way myself, although for some reason I've drifted into operating system design. Actually, I'm currently doing Forth which can simultaneously be interactice, a simple OS, and remarkably close to the metal.

I especially hate update madness, on which point you should know that my OS-developing friends ran into trouble on the RPi 4: the device tree format was changed separately from any hardware update. My friends kernel could no longer find the device IDs at build time. IMO, that's a horrible example of update madness. My friends also had a little problem with 8GB Pis having some unexpected difference from 4GB Pis. That's a little bit more normal in the hardware world.

Raspberry Pis have never been the most open, best quality, or most powerful SBCs for their price. The Pi 4's quality is okay, but see above. Their best point is that they're available in more countries than any other open or semi-open SBC. (Given the mountain of paperwork many countries require for electronics, including the complete lack of EU unity in this area, this is quite an achievement!) They do have some good points. Having a coprocessor (GPU on the Pi) handle a lot of tasks must be very helpful for bare-metal development, especially for beginners. And because the Pi is so very popular, it doesn't take terribly long for all the undocumented parts to be documented.

Some seemingly closed systems get opened up pretty well, including some fairly powerful smartphones, although the only documentation often ends up being Linux driver source. If you can stomach reading it, it might be worth checking out PostmarketOS, a Linux distribution for obsolete smartphones. However, some people say "Reading Linux driver source is where the fun stops."

If you're looking at SBCs in general, bear in mind some SoCs are much more complex than others, and it isn't entirely related to how powerful they are. For instance, years ago, I wanted to develop bare-metal for my already-old Kindle 4. I got the data sheet for the SoC, got very confused, and gave up. This SoC was nothing special; single ARM core, 128K each RAM & ROM, maybe DRAM & SD controllers, and that's about it. A year or two later, my super-smart friend, a physics student at Cambridge, developed his own SBC around a Zynq SoC: dual-core ARM with FPGA on board, a really nice bit of kit. At one point, he found it a bit of a headache. I asked him how many pages the datasheet had. I'm not joking when I say it was about 20% smaller than the datasheet for the old Kindle's SoC! I didn't feel so bad about giving up after that. :)

Did you know you couldn't entirely get the OS out of the way in the 8-bit Atari 400 and 800? It always responded to vblank. You could cut out the majority of what it did in vblank, but not all of it.

If you want something really wild, try to get hold of a GA144 - 144 tiny computers on a single chip. :) They run at about 700 MIPS with 4 instructions per cycle. They only have 64 18-bit words of RAM and ROM each, though. ;) It can be hooked up to RAM and ROM, but dynamic generation is obviously a big thing, which of course involves cycle counting. Timing is primarily done by cycle counting. The eval board has a VGA port, and I'm sure it would be easy to hook up the chip's 2 spare DACs for audio - just right for demos, no? (Actually, the board has 2 GA144s. Surround sound demo? ;) There was a cheaper board too, but the power rails weren't decoupled well enough, so it's flakey. I'm apparently not gloepy enough to post links, so you'll have to search greenarrays and paste colorforth.github.io (it's a mirror). Greenarrays has some GA144 stuff on the front page as I write. On the colorforth site, see the "eval blog" link, it's Charles Moore's record of developing for the GA144 and a predecessor. He starts with dynamically generating video. Oh by the way, it's a Forth chip, ;) but 18 instructions is easy to learn no matter what language you think of them as. (Or maybe 21, not sure.) Oh... documentation for some parts of the chip seems a bit light. I think if you buy an eval board, you get to talk to the company, maybe? It's a small company. Or maybe the simulator helps you understand. It's free.

Speaking of dynamic generation, one of my minor goals is to bitbang video and audio with a more convential microcontroller, essentially making a display and maybe demo with a device never meant to drive a display. :D Some microcontrollers can be powerful; I don't think there's a clear line between them and SBCs. I've recently bought some BBC microbits. They have ARM cores, albeit with only 16KB RAM. (There's more ROM.) Not quite sure they're powerful enough for video, but will have fun trying. Might have to settle for a PAL or NTSC resolution rather than VGA. Got an Arduino Mega too, although I mostly bought that for all the junk that came with it. Haven't got started with them though. (Somebody buy me a round tuit.)

Returning to coprocessors, the microbit has a coprocessor which A: handles flashing the ROM, and B: is not itself programmable. The combination makes it impossible to brick the board. Having gone through the scary process of flashing brickable devices in the past, I very much appreciate that! :) It's also impossible to brick a device with an unflashable boot rom, if I understand right, and some boot roms are nice enough to just load your 'kernel' and leave all the fun stuff to you.
added on the 2020-07-27 21:19:56 by eekee eekee
cuda
added on the 2020-07-27 21:25:38 by abductee abductee
Tuna, because it's a whole bunch of posts in one. Baracuda hunt singly, tuna in groups.
added on the 2020-07-27 23:08:49 by eekee eekee
Well... FPGA.
added on the 2020-07-28 19:50:33 by dex46... dex46...
Minuteman's ZZ9000 Amiga gfx card with ARM cores on FPGA. :)

But what about ESP32 (mentioned before), 240 MHz dual core or single core with FPU, companion chip (RISC V in most recent model), and available on boards with touchscreens? WLAN, BT, audio capable board variants...
And NO OS.
So, have you been able to do anything with the Pandora?
Otherwise, I was gonna suggest the GP2X or GP32. Not so recent but at least they're 32bits. From what I remember on the GP2X, you had to put a line of code when your program ended to restart the GUI. :D
added on the 2020-07-30 03:26:35 by BarZoule BarZoule
Quote:
If you want something really wild, try to get hold of a GA144 - 144 tiny computers on a single chip. :)


This reminds me of the Propeller 2, the successor of the hardware this fine demo was made for.

Quote:
Minuteman's ZZ9000 Amiga gfx card with ARM cores on FPGA. :)


It's mostly an ARM CPU with a framebuffer, and an FPGA for the boring tasks (eg. bus control, interfacing everything with the amiga properly, etc.)

Quote:
GP32


Well there's also the Nintendo DS :p I'd love to have some competition for it!
added on the 2020-07-31 00:39:32 by porocyon porocyon
I managed to get my Pandora running (and update to latest OS as well), and I actually also ordered a RasPi 4, if I end up wanting to give RISC OS another go.

However, I soon realized that for both of these options to actually be able to compile any code, I would need to set up some kind of GCC-ARM cross-compiling environment, meaning I'd need to install a Linux VM and then all that other crap that is needed, and then it started to feel a bit too close to "work" and too far from "fun"... :)
added on the 2020-08-01 00:02:39 by Sdw Sdw
GCC works on windows and osx as well, no?

(on windows you could also use mingw, msys or cygwin)
added on the 2020-08-01 02:13:53 by porocyon porocyon

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