I’m documenting my process to programming a Xilinx FPGA I have my possession. I currently have the RedPitaya that I got for some analog applications I was originally interested in. I plan on getting a MicroZed since it seems to be more configurable and doesn’t use so much (or any?) of the FPGA pins.
I’m runing Fedora 25 on a 64 bit Intel Laptop with 16 Gigs of RAM. There seems to be a few bugs with Wayland so I’m still running Gnome Shell with X11. I’m attempting to install and run Vivado WebPACK 2016.4.
Download Vivado, then change the permissions of the downloaded file to allow execusion, and install as root:
chmod +x Xilinx_Vivado_SDK_2016.4_1215_1_Lin64.bin
sudo ./Xilinx_Vivado_SDK_2016.4_1215_1_Lin64.bin
When prompted, I enable downloading and installing the SDK. I disabled anything that didn’t have to do with the Zynq chips. This made the download ~3.8GB in size.
When prompted to save the link for a license somewhere you can find it. I
just saved it in I think that the WebPACK license is free and doesn’t
require anything. I’m not too sure, I’ll have to wait until something
complains./.
I got bored of starting Vivado from the command line, so I created some packages for nice desktop files for Fedora. Download the appropriate package by issuing the following commands
sudo dnf copr enable hmaarrfk/useful_launchers
sudo dnf install vivado-2016.4-desktop.noarch
Minicom is necessary for piece of mind when booting up your FPGA for the first time. It will give you access to the serial port output of the FPGA making it the easiest way to connect.
sudo dnf install minicom
You need to add yourself to the dialout group to use the /dev/ttyUSB0 that
appears when you try to interface the FPGA through the COM port. This makes
configuration very easy.
sudo usermod -a -G dialout YOUR_USER_NAME
For some reason, you have to reboot your computer if you are on Gnome Shell for things to take effect. That shouldn’t take too long if you have an SSD.
We can configure minicom without having the RedPitaya workign for the moment. Open minicom with:
sudo minicom -s
use j and k to navigate down and up respectively, enter to select.
Open Modem and dialing. Select entries with the appropriate letter on the keyboard. Type as usual, and enter to finish.
Clear entries C through L. You don’t need these for connecting to a serial port.
Open Serial port setup. Change the Serial Device to /dev/ttyUSBO. If your Red Pitaya appears as a different device, then use that device. It will probably be just a higher number on the /dev/ttyUSBX.
Leave Bps/Par/Bits as is to 115200 8N1. (115200 bits per second, 8 bit ber byte, No parity, 1 bit stop), but set Hardwave and Software Flow control to No.
You may choose to save as default (dfl or Save setup as.. if you wish).
If you happened to exit minicom, you can now open minicom with your regular user
minicom
This great repository by Pavel Demin Exists on Github. Clone it
git clone git@github.com:pavel-demin/red-pitaya-notes.git
These tools seem to be necessary to develop Pavel Demin’s code. This isn’t an exhaustive list since I use my laptop for other development as well and I can’t be sure what else I instaled. Let me know what error messages you get and I’ll be glad to help you debug things.
sudo dnf install dtc uboot-tools debootstrap qemu-user-static zerofree
Technically, I don’t think you need debootstrap, qemu-user-static, or
zerofree if you are going to download Pavel’s prebuilt image. I just like to
install things from scratch when I can to learn as much as I can.
I’m not really sure how I got this one working. I’ll try to follow these instructions again on a
new computer when I have the time. You need to enable binfmt to create the SD card. binfmt is
crucial for executing arm programs on your intel computer. I think the idea in doing so is that
an arm emulator on your computer is faster than an actual arm processor. While that may be
true, Pavel’s scripts run directly from the SD card, which I think might make things slower
than they should be. In either case, we will simply follow his lead.
You can check the status of binfmt with
sudo systemctl status systemd-binfmt.service
Start it with
sudo systemctl start systemd-binfmt.service
I think the following command should enable it to start on default when your computer boots:
sudo systemctl enable systemd-binfmt.service
This should finally allow you to run the scrits that create the SD image from scratch.
You are now ready to boot up your Red Pitaya. Safely remove your SD card if you haven’t already, plug it in the Red Pitaya, connect a USB cable between your computer and the COM port on the Red Pitaya, and connect a 2A power supply to the PWR port.
Let the Red Pitaya Boot. It should spew near nonesess on your computer. If somebody can figure out
how to let minicom interpret UTF-8, I would be very happy to know. In either case, you shouldn’t
need to use minicom too much after setting up your FPGA. It is a very slow communication method,
only 115200 bits per second, or 14kbps, back to the dialup era.
You’ll now have access to a log in prompt, asking you for a username (root) and a password
(changeme).
Orignally, the RedPitaya requires you to have a wired connection, on a dedicated ethernet port between your computer and the FPGA. You probably don’t have that luxury on a laptop. In either case, I’ll walk you through both setting up a wired bridge between your laptop’s Wifi access and the RedPitaya and connecting your RedPitaya directly to your home wifi network.
Follow the instructions
here to
bridge your home wifi to a wired connectors for your Red Pitaya.
You will want to edit the file /etc/network/interfaces.d/eth0 to contain the following
allow-hotplug eth0
iface eth0 inet dhcp
(it might also need a line auto eth0, but I’m not too sure at this point). I think it is easier
for your to pop in the SD card on your computer and edit the file with your favorite editor. Once
you have configured the bridge, you should restart the Red Pitaya so that it takes to the new
configuration.
You might want to invest in a USB wireless adapter I got bored of all the cabling, and for a simple testing rig, I decided it was probably easiest to get a wifi card working for the RedPitaya. Of course, easier said than done right ;).
I worked with Pavel Demin on GitHub
to help understand how to get it all working. It turns out that the drivers aren’t yet available
for Debian Jessie and that you had to copy it manually
from newer kernel versions. The details are in the
issue linked above.
Make sure /etc/network/interfaces.d/wlan0 contains:
allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
wpa-ssid YOURNETWORK_SSID
wpa-psk WPAPSKHASH
You can encrypt your wpa-psk passphrase by adapting
wpa_passphrase myssid my_very_secret_passphrase
Boot up your RedPitaya and voilà. Let me know if you have any questions. Happy coding.
My next post will be focused on deciphering what Pavel Demin is doing with all his scripts.
It seems no matter how much you try to simplify things, you can never truely simplify hello world!.