Help with Using a Virtual Python Environment and LiteX

[DoctorWkt]

I wanted to play with FemtoRV and LiteX, but my Linux environment won't allow me to install Python modules with pip3 and I need a virtual Python environment.

So here are some commands which helped me get it working in such an environment. Some of the commands come from https://blog.bomorgan.io/hobbies/hardware/fpgas/litex-riscv-ecp5-ulx3s/.

Install System Dependencies

Install the Python venv module:

$ sudo apt-get install python3-venv

Set Up the Python Virtual Environment

Create a virtual Python environment in a new directory (the name isn't important) and activate the environment:

$ mkdir litex-riscv-ulx3s && cd litex-riscv-ulx3s
$ python3 -m venv venv && source venv/bin/activate
$ pip3 install meson ninja

I decided to install meson and ninja at the same time. From now on, until you type deactivate, you are using this virtual Python environment. If, later on, you want to activate this environment again, you need to:

$ cd litex-riscv-ulx3s && source venv/bin/activate

Download and Set Up LiteX

Now, while we are in the litex-riscv-ulx3s directory, we can download and set up LiteX:

$ wget https://raw.githubusercontent.com/enjoy-digital/litex/master/litex_setup.py
$ chmod +x litex_setup.py  && ./litex_setup.py --init --install
$ cd ..

Build a Bitstream

LiteX is now installed along with the virtual Python environment.

Now we go to where we have the learn-fpga repository and, for example, build a bitstream for an ULX3S board:

$ cd learn-fpga/LiteX
$ python3 -m boards.radiona_ulx3s_ex --device LFE5U-45F --sdram-module MT48LC16M16 --cpu-type femtorv --cpu-variant petitbateau --build --load --ecppack-compress

Connect to the Board

The above command loads the bitstream on to the ULX3S board. When this is done, you should see the LiteX LED heartbeat on the board. You can then open a terminal on the USB serial port appropriate for you. I use:

$ minicom -D  /dev/ttyUSB0

and I see:

--============= Console ================--

litex> sdram_test                                                                                    
Memtest at 0x40000000 (1.0MiB)...                                                                    
  Write: 0x40000000-0x40100000 1.0MiB                                                                
   Read: 0x40000000-0x40100000 1.0MiB                                                                
Memtest OK

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