Preferred AXI bus type for a real time application

[rt54321]

Greetings All!

Using an Arty Z7, I'm trying to migrate a real time motor control application from a microcontroller to the Arty Z7.  My goal is to eventually implement the inner current control loop (running at 20kHz) in the PL fabric for high speed using Vivado HLS, while one of the two A9 cores runs the slower tasks (like velocity control), and the other A9 core runs the user interface.

With the real time determinism in mind, do I want to make my PL interface bus with an AXI4 "full" implementation, AXI4-Lite, or AXI4-Stream?  From what I can see in the Xilinx App notes, AXI4-Stream is more for image processing, which is not what my intentions are.

 

 

[zygot]

No doubt that you will get a lot of suggestions on this.

Without knowing the specifics of what you are trying to migrate I doubt that your choice of PS/PL AXI bus will be of consequence from a performance viewpoint.

There are a lot of ways to approach this but I'd suggest trying to make your design as simple as possible. Either core in the PS should be able to implement the whole thing unless I'm misunderstanding your requirements. A fixed point HDL design in the PL would certainly work as well, though I'm assuming that your mention of Vivado HLS means that you don't want to do Verilog or VHDL design work.

XAPP1163 might be of interest, though this uses ISE.

Implementing this is as a design exercise one thing but implementing it connected to a motor is another. If you want to control a motor then you should start with specific HW interfaces as this might drive the rest of the design partitioning.

The normal PS/PL interconnects might not be the ideal way to pass data between these parts of a given design. You can use UART or SPI sub-systems in the PS that aren't use on the board by using the EMIO as a simpler way to do this.