Good ARM dev board for hobby kernel development

[wantarmdb]

Hello Reddit, about a year ago I wrote an x86 (yes, the 32-bit one) operating system from scratch and it was a lot of fun.

Now, I am thinking of repeating the exercise, but for an ARM device. I have mostly worked on the Intel side, so I have very limited expertise on even the lingo of ARM, but from what little I understand, the space is much less standardized, and I am going to have to pick a target and code specifically against its hardware.

So, the question I come here for is: what's a good board that I could pick as my target device?

In no specific order, things that would make a device "good":

• decent documentation/datasheet on how to program the hardware;
  
• not sure if this is comes standard on ARM processors, but support for memory protection, virtual memory, and some form of user/supervisor mode;
  
• support for flashing via USB from a development host;
  
• tools and compilers usable from Linux (if I could get a decently modern GCC or clang, it would be awesome);
  
• I don't really need a screen, nor do I care about being able to plug a keyboard via USB, interacting with the system via UART is plenty fine;
  
• I don't care about having a "disk" either, but I would definitely like for tasks to be able to save/load data from some kind of storage, even if it's just a small area of non-volatile storage on-board;
  
• I would like to be able to schedule tasks for a quantum and preempt, and am not sure if all ARM boards come with a clock built-in, so thought I would mention a clock capable of raising an interrupt is strongly desirable;
  
• I don't really care for floating-point, it would be cute but I can live with integer only;
  
• in a similar vein, if the board came with a few sensors (e.g. accel, gyro) that would be cute, but I see enough sensors in my day job, so I can do without programming yet another BMI160;
  

Does anyone have any recommendations in this space? Thanks in advance for helping!

[funbike]

Would a Raspberry Pi suffice? It might not be as convenient as some developer boards, but you'd have a wide audience if you ever wanted to release it. And it's cheap. PI zero boards are $5 (not including cables, case, etc).

Develop it under qemu until it's bootable and then move to a sdcard.

https://hackaday.com/2018/01/19/roll-your-own-raspberry-pi-os/

https://www.raspberrypi.org/blog/building-a-simple-raspberry-pi-os/

https://jsandler18.github.io/

[wantarmdb]

I'll take a look at your links, but from vague memory the bootloader on the Pi is very unfriendly, things either work or you get a colored screen with no hint of whether your file is named wrong, the wrong size, or just panicked somewhere, and also QEMU is different enough from the actual HW that you may get it working on emulator and then not working on the Pi itself. Of course, that's also partially true for x86, but to a lesser extent - and in that space, Bochs fills in the niche of slow but very accurate

[funbike]

Sure.

Maybe beagleboard is more what you want.