Remora for RK3588 Boards

The docs are secretly hidden here: (so don't tell anyone)
github.com/Hao-boyan/rk3588-TRM-and-Datasheet

Hi,
the RK3588 is a very powerful chip. It requires careful PCB design and hence not easy to replicate.

In my opinion it would make more sense to port remora to other architectures, like the CH32V307, also mentioned in cnc-club.ru:

www.cnc-club.ru/forum/viewtopic.php?f=15...74b124058&start=1360

The CH32V307 is a MCU, the rk3588 is a SOC that contains 8x cpu and 3x M0 MCU. The reason to port remora for the M0 cpu is so you would only need a SBC with that rk3588 chip.

As you could see in the other thread, the Orange Pi 5 with the low latency kernel has a low latency, about 6uS on the base thread, so even without using the mcu it's usable. With Remora on the MCU it might even improve further. But it's the question if the MCUs aren't already in use for other tasks. As far as I could see there is one MCU programmable, not sure if this mcu is powerfull enough to improve over the cpu.

If you want to build your own board, why not use a stm32 where Remora is build for?

Even if you get the internal cortex-m0s to cooperate (assuming they are not used by the firmware for power management and related system management stuff) you still need a RK3588 board that has enough accessible I/O Pins. Then you need a breakout board. On the breakout board you could easily include a ~1US$ microcontroller, talk SPI to it and be done.

Yes, that's true. But there are breakout boards available for it that already have LAN on board. For making steps in realtime this would be also more than enough.

The Orange Pi 5 was not known for me, but it sounds really interesting.
One could implement remora on the Orange Pi 5 and use that as stepgen and finally it would have enough power for driving fancy displays :lol:

After all, in my opinion it is better to have a system composed of multiple simple parts, than a large monolith. With a monolith you depend on the provider of the monolith.

Now you can use a standard x86 PC with any remora enabled card. You are free to replace either the one or the other.
Do you need GPU for watching youtube while machining? No problem.
A second network interface? Just insert a new network card.
This is a huge benefit especially for open source community.

Yes, an STM32 would be the first choice, if it is available again.

Yes, maybe "remora" name should be reserved for projects that use an external MCU interfaced over SPI (or Ethernet) to LinuxCNC. Using an integrated MCU seems cool, but it's not clear how it is interfaced (shared memory maybe?) and how is firmware flashed to it. This is something that was already done in the past with  allwincnc project . Hard to say if similar approach is applicable to RK3588 with it's integrated Cortex-M0 core.

Until this is investigated, Remora can be used with RK3588 with an external MCU. It's SPI implementation is using bcm2835 library which will only work on RPi hardware. When porting Remora to UP Board, Mr.Bubbles rewrote this SPI code to use spidev (should work with RK3588 as well as any board with SPI kernel driver), however this implementation appears to have  realtime performance issues .

So finally, it leaves us with Ethernet. Will it work? Most likely, yes. Anyone already tried it? I don't think so.