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opensecura / 3p / lowrisc / opentitan / 0303964365696c5c83cb9439039cd32253985eee / . / hw / vendor / lowrisc_ibex / examples / fpga / artya7
tree: c457c826200db5fafd4dc99baff2431707151e1b [path history] [tgz]
  1. data/
  2. rtl/
  3. util/
  4. README.md
  5. top_artya7.core
hw/vendor/lowrisc_ibex/examples/fpga/artya7/README.md

Ibex RISC-V Core SoC Example

Please see examples for a description of this example.

Requirements

Tools

  • RV32 compiler
  • srecord
  • fusesoc and its dependencies
  • Xilinx Vivado

Hardware

  • Either a Digilent Arty A7-35 oder A7-100 board

Build

The easiest way to build and execute this example is to call the following make goals from the root directory.

Use the following for the Arty A7-35

make build-arty-35 program-arty

and for the Arty A7-100

make build-arty-100 program-arty

Software

First the software must be built. Go into examples/sw/led and call:

make CC=/path/to/RISC-V-compiler

The setting of CC is only required if riscv32-unknown-elf-gcc is not available through the PATH environment variable. The path to the RV32 compiler /path/to/RISC-V-compiler depends on the environment. For example, it can be for example /opt/riscv/bin/riscv-none-embed-gcc if the whole path is required or simply the name of the executable if it is available through the PATH environment variable.

This should produce a led.vmem file which is used in the synthesis to update the SRAM storage.

Hardware

Run either of the following commands at the top level to build the respective hardware. Both variants of the Arty A7 are supported and can be selected via the --parts parameter.

fusesoc --cores-root=. run --target=synth --setup --build lowrisc:ibex:top_artya7 --part xc7a35ticsg324-1L

fusesoc --cores-root=. run --target=synth --setup --build lowrisc:ibex:top_artya7 --part xc7a100tcsg324-1

This will create a directory build which contains the output files, including the bitstream.

Initial memory parameter SRAMInitFile can be given to FuseSoc to specify which .vmem file to load the design with. Example use case includes loading coremark.vmem which can be used for performance/power analysis.

Please see CoreMark README for compiling CoreMark.

fusesoc --cores-root=. run --target=synth --setup --build lowrisc:ibex:top_artya7 --part xc7a100tcsg324-1 --SRAMInitFile=examples/sw/benchmarks/coremark/coremark.vmem

Power Analysis Using Vivado

Setting FPGAPowerAnalysis parameter to 1 allows user to run a power analysis using Vivado. It uses a post-implementation functional simulation on Vivado to log switching activity. This switching activity is then used to generate a detailed power report. In order to use it with CoreMark run the command below

fusesoc --cores-root=. run --target=synth --setup --build lowrisc:ibex:top_artya7 --part xc7a100tcsg324-1 --SRAMInitFile=examples/sw/benchmarks/coremark/coremark.vmem --FPGAPowerAnalysis=1

Program

After the board is connected to the computer it can be programmed with:

fusesoc --cores-root=. run --target=synth --run lowrisc:ibex:top_artya7

LED1/LED3 and LED0/LED2 should alternately be on after the FPGA programming is finished.