Skidbuffer with LFSR is a design that inserts pseudo random timing interruptions in a AXI streaming data flow. This is usefull test the AXIS interfaces of new blocks. The skidbuffer-tester repo demonstrates how skidbuffer LFSR in a Zynq DMA transfer. The project is setup for Zedboard, although it would be easy to change to other boards assuming you have some basic TCL skills.
Here is an example were 400 intergers are sent via DMA. Normally you dont see any contention.
However, without contention it is not possible to really test an AXIS interface. Skidbuffer + LFSR inserts these short contentions in the dataflow, testing the interface protocol of a block with AXIS. This is what happens to the same data transfer after Skidbuffer + LFSR block. Every time you run, the timing is a bit different thanks to the LFSR.
This IP interface consists of a AXIS slave and a AXIS master ports.
It has parameter to adjust the data width, the LFSR seed, and if the LFSR is used. The mode without register is not working yet. Dont disable it.
This repository might have custom IPs included as git submodules. Thus, the following command is required to download all its dependencies.
git clone --recursive https://github.com/amamory/<repo-name>.git
If you already cloned the repository without --recursive, then run the following command to download all the submodules.
git submodule update --init --recursive
Refer to this tutorial to learn how to manage submodules.
These scripts are assuming Linux operation system (Ubuntu 18.04) and Vivado 2018.2.
Follow these instructions to recreate the Vivado and SDK projects:
- Open the build.sh script and edit the first lines to setup these environment variables:
- VIVADO: path to the Vivado install dir;
- VIVADO_DESIGN_NAME: mandatory name of the design;
- XIL_APP_NAME: used only in projects with software;
- VIVADO_TOP_NAME: set the top name (optional).
- run build.sh
These scripts will recreate the entire Vivado project, compile the design, generate the bitstream, export the hardware to SDK, create the SDK projects, import the source files, build all projects, and finally download both the bitstream and the elf application. Hopefully, all these steps will be executed automatically.
These scripts come from a template repository and they get updated and improved over time. If you wish to get the latest script version, then follow these steps:
git remote add template https://github.com/amamory/vivado-base-project.git
git fetch --all
git merge --no-commit --no-ff template/master --allow-unrelated-histories
Solve any conflict manually and then commit.
- update the scripts to Vitis
- support or test with Windows (help required !!! :D )
The scripts are based on the excellent scripts from fpgadesigner plus few increments from my own such as project generalization, support to SDK project creation and compilation and other minor improvements.