Deference between soc and soft processor

[sala77]

I want to implement a motor control on the FPGA, I am going to use a processor in my project, I have two way to do that, use an ARM Hard processor or use NIOSII soft processor? I know hard processor if faster then soft processor. but altera do motor control by NIOSII soft processor on the FPGA have soc , why?

 

[shaiko]

A "soft processor" is a processor that's implemented using the programmable logic of the FPGA.
It's usually much smaller in size and has lesser performance than a Hard Silicon device - For example: Nios II vs ARM Cortex A53.

An SOC ("System On a Chip") is an ambiguous term that has more to do with marketing than with engineering. There're no clear boundary as to when a device becomes an SOC.

There can be a number of benefits to using a soft processor (for example NIOS II) instead of a hard one (ARM Cortex A9):

1. As I mentioned it's smaller in size.
2. It's configurable.
3. It's less complex to set up and write code for.
4. It usually has better interrupt latency.
5. You can instantiate a large number of cores and have each do a very specific task.

If the soft processor can handle the task well, without consuming too much FPGA resources - why not use it ?