Using FuseSoC for automation¶

Topwrap uses the FuseSoC package manager and build tools for HDL code to automate project generation and the build process. When topwrap generate is used with the --fusesoc option, it generates a FuseSoC .core file along with the top-level wrapper.

Default tool for synthesis, bitstream generation and programming the FPGA¶

Topwrap assumes that you’re using Vivado. You can change the default tool to something other than Vivado by modifying the generated .core file.

Additional build options¶

To enable .core file generation, supply --fusesoc to topwrap generate:

topwrap generate design.yaml --fusesoc

If you have any additional directories with HDL sources or constraint files required for synthesis, you can specify them using the repeatable --sources option. Sources from these directories get appended to the filesets.rtl.files entry in the generated FuseSoC .core file.

topwrap generate design.yaml --fusesoc --sources ./srcs_v --sources ./srcs_vhd

If you’re targeting a specific FPGA chip, you can additionally specify its number using the --part option.

The supplied part number is passed to the FuseSoC .core file. It is included in the targets.default.tools.vivado.part entry, which is then supplied to Vivado when you run FuseSoC and use the default target. This can be any part number available to your local Vivado installation.

topwrap generate design.yaml --fusesoc --part 'xc7z020clg400-3'

Library-backed IPs used by the design are emitted as dependencies of the generated core. FuseSoC therefore includes their own RTL filesets when it builds the design.

Use --target-dir to change the output root. The wrapper and .core file are written to its src subdirectory.

The generated core currently defines a default Vivado target. Edit the generated .core file if another tool, additional targets or hooks are required.

Synthesis¶

After generating the .core file, you can run FuseSoC to generate the bitstream and program the FPGA:

fusesoc --cores-root build/src run {design_name}

This requires having a suitable backend tool that is specified in the .core file under targets.default.tools available in your PATH (e.g. Vivado).