[Bad Wolf]

What a DSP/FPGA or microcontrolller does well is the fine grained timing requirements that is necessary for low jitter step pulse output.

There are some step generation hardware that is good to several MHz. I use a uc300eth that can do couple hundred kHz step pulse. A super fast PC cannot do that without using some kind of external hardware or pci card.

Sort of see where your coming from, but this chip isn't processing data, it is timing data, unless "processing" is being used in a generic sense as a given amount of throughput.
I know a lot of the people who understand audio far better than me talk a lot about timing, so I could see how an external chip to perform timing could be beneficial for this purpose.

[ger21]

How the trajectory planner is coded has a lot more to do with how the machine runs than the processor.

[Beefy]

As a calculated GUESS I would also tend to think it's all about timing, and not data throughput. Yes an ethernet connection is super fast with data throughput, but I bet it can't time that throughput precisely in a way that's needed for step pulse generation.

Windows PCs are also multi-tasking machines where they jump from one process to another. And don't ethernet connections send data in "packets". If a PC could deal perfectly with timing I'm sure we wouldn't have any external motion controller boards.

[battwell]

i mainly make cabinet parts with uccnc- where everything must clip and fit together- so accuracy is paramount.
not once have i had to switch to g61 exact stop mode :-)
i upgraded from usb 300 to 300eth (as id nagged balacz to make it in the first place. -and so glad he came through with such a great product)
i leave my pc on all the time, unlike mach3 it doesnt require restarts after a few days when things stop working etc. uccnc only gets restarted when i add a new plugin etc now
here is a video of it running a nested job- its doing this day in day out - couldnt be happier!
im running uccnc with uc300eth, 3 cheapy £5 chinese break out boards, mitsubishi servos in position mode.
ive since added a toolchanger rack and have tool length probing for fast start work with any new tool.
https://youtu.be/veb6rAmkS9Y

[A_Camera]

As a calculated GUESS I would also tend to think it's all about timing, and not data throughput. Yes an ethernet connection is super fast with data throughput, but I bet it can't time that throughput precisely in a way that's needed for step pulse generation.

Windows PCs are also multi-tasking machines where they jump from one process to another. And don't ethernet connections send data in "packets". If a PC could deal perfectly with timing I'm sure we wouldn't have any external motion controller boards.

Not only that, but Ethernet packets collide all the time, so there is a collision detection procedure which makes sure that packets are sent and received without error, which means some packets are resent. Packets are also not always sent in sequence, so it is pretty complicated. The motion controller board receives the packets, assembles in the right order and sends the timed signals to the steppers. There is probably no other processing, processing takes place in the UCCNC software.