My mother asked me what kind of sweater I would like her to knit for my son. After some thinking I decided I wanted him to have Tux on his sweater. I found a picture of tux, reduced the resolution to how many masks would fit on the sweater and did some manual correction of pixel colours. I also wanted the picture to have a grid and numbered ticks. This is not something the normal print dialog offers to do for you, but it can easily be done in Python using Matplotlib.

Common mode choke Recently I assembled a Common mode choke from HFkits to use with my vertical antenna that, due to space restrictions, do not have radials as counterpoise. This common mode choke should cover the HF band from 3MHz to 30MHz. A common mode choke should prevent the outer conductor from radiate. And it may prevent noise picked up from the outer conductor to reach the radio. This is how the kit after I opened the package.

In our previous posts we have built the bootloader and the Linux kernel and put them on a SD Card. Now we will also add a root filesystem to complete our GNU/Linux system. There are many different root file system we could have used, Yocto, Debian … but I chose ArchLinux ARM since ArchLinux is my preferred GNU/Linux distribution. First we download ArchLinuxARM. $ cd $ wget http://os.archlinuxarm.org/os/ArchLinuxARM-armv7-latest.tar.gz We are going to add another partition to the image file we created earlier.

In the last post we compiled the boot loader and booted into U-Boot. Now we will continue by building the Linux kernel and adding it to the SD Card. First we clone the kernel from github, list the branches and checkout the branch we would like to build. $ git clone https://github.com/altera-opensource/linux-socfpga.git $ cd linux-socfpga $ git branch -a $ git checkout -b sockit-5.8 remotes/origin/socfpga-5.8 When that is done we configure the kernel.

In order to be able to boot GNU/Linux on the Arrow SocKit we need a bootloader. If we run make we see that there is a target called uboot. $ cross_compile_arrow_sockit $ quartus20.1 ———————————————— Altera Nios2 Command Shell Version 20.1, Build 711 ———————————————— $ eds20.1 ———————————————— Intel FPGA Embedded Command Shell Version 20.1 [Build 711] ———————————————— $ make ***************************************** * * * Manage QuartusII/QSys design * * * * Copyright (c) 2015 * * All Rights Reserved * * * ***************************************** ********************* * Target: help * Displays this info (i.