Inside the Retron 77

[DirtyHairy]

During the past two weeks, I have spend some time disassembling the R77, examining the hardware and digging through the source drop published by Hyperkin. The results are documented in the Stella wiki on GitHub: https://github.com/stella-emu/stella/wiki/Retron-77

 

It is pretty technical, but that was my intention: to provide a starting point for anybody who'd like to start hacking the device. Please tell me if there is anything missing

Edited July 11, 2018 by DirtyHairy

[Andromeda Stardust]

if this device can be hacked or modded to add features or compatibility, im all for it. as it is out of the box, it could definitely use some improvement.

[+stephena]

I've added quite a bit of information on what would be required to get Stella 5 running on this device. While it isn't insurmountable, it will require someone (or a group of someones) that have Linux experience and some fairly cheap hardware to interface with the device.

[+Atari_Warlord]

I don't have the skills, but an interesting read anyway.

[Andromeda Stardust]

is there some reason the hardware would struggle with it? i assume the gpu is capable of whatever hardware acceleration modes were added in stella v4. whether it is fast enough is another question entirely.

[Thomas Jentzsch]

The CPU is more than powerful enough, even for future Stella versions.

[Keatah]

I don't have the skills, but an interesting read anyway.

 

It's always a good thing to read material like this, even if you (me) don't fully understand it. "Enough" understanding is usually sufficient to prevent pestering the developers by informing you of something they're already working on. On the other hand it may also grease the wheels and promote thought about new and unplanned future features.

 

And "enough" understanding may also help you use a given product differently or better, or simply solve a problem you didn't know you had.

[+Karl G]

Would building X for the system for SDL2 to use as a backend be an alternative to updating the kernel and patching SDL2 to support the graphics hardware?

[+stephena]

is there some reason the hardware would struggle with it? i assume the gpu is capable of whatever hardware acceleration modes were added in stella v4. whether it is fast enough is another question entirely.

 

One of the links I added mentions that this same hardware, with the updated SDL2 and Mali drivers, can run Quake 3 at 90+fps. Quake 3 is much more physically demanding than Stella will ever be. Even with all graphical filters enabled.

 

The problem is strictly getting the software updated. I don't foresee any problems with speed issues, either for the CPU or the GPU.

[+stephena]

Would building X for the system for SDL2 to use as a backend be an alternative to updating the kernel and patching SDL2 to support the graphics hardware?

 

SDL2, Mali and X will result in much slower graphics. And besides, it's much harder to do that, since you still need to get the kernel and SDL2 supporting the GPU. Then after that, you have to get X working with it too. On this type of embedded system, using X is just extra baggage that will slow things down.

[DirtyHairy]

Would building X for the system for SDL2 to use as a backend be an alternative to updating the kernel and patching SDL2 to support the graphics hardware?

 

 

You might also run into issues with RAM: the R77 only has 128MB to start with, and the current setup even uses part of this for the initramfs (which is the *full* rootfs and never gets unmounted). At the very least, you'd have to trade the initiramfs setup (which is pretty elegant imho) for a full-blown ext2/3/4 partition on the SD card, and even then RAM might not be sufficient without adding a swap partition

Edited July 12, 2018 by DirtyHairy