15 Jan 10 Embedded Linux Programmer

As an embedded linux programmer, I’ve had the opportunity to work on a number of different platforms, MIPS being one of my favorites.

There are a few general limitations that you’ll find. You have limited CPU power available, you have very little RAM available, and for more advanced operations and optimizations, your CPU will generally have a limited function set.

The usual good programming practices apply, but are of much greater importance. Specifically, don’t allocate memory that you don’t need, and dont put the CPU under undue stress with unnecessary or badly optimized loops. Taking C syntax and some pseudo code;
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Tags: assembler, embedded, loop, mips, optimize, x86

19 Sep 09 Installing Linux on the Embedded PPC50 Touchscreen

I personally really like this touch screen PC! I’ve installed Debian (of course), graphical interface, and configured the HUAWEI data card along with the TSCOM touchscreen drivers.

I also modified the boot up to log in and start the graphical interface automatically. Using xvkbd for a virtual keyboard works really well, and I might just have to carry this around in the car along with the datacard for those emergency situations.

It’s a simple x86 with 1GB diskspace and 1GB RAM. The device takes a simple 12V/6A input and therefore wiring it up to a car, battery, or other portable power supply shouldn’t be a problem!

Any ideas what next?

Tags: datacard, debian, embedded, Huawei, Linux, ppc50, touchscreen, tscom, x86, xvkbd

19 Oct 08 Linux on a Mikrotik 532a , Part 5 Final – OpenWRT and Custom Scripts

Follow on from: http://www.adamsinfo.com/linux-on-a-mikrotik-532a-part-4-customization-debian-scripts-shaping-firewall-nat-picolcd/

Discuss this article here

I’ve used OpenWrt previously to this project to build some firmwards for the Linksys Router WRT54 range. OpenWrt is an incredibly powerful and small Linux distro. Although debian is probably better suited to the reasonably powerful hardware, I wanted to give OpenWrt a go anyway.

Unless you’re running a MIPS 4Kc processor on your host which I’m guessing you’re not, you’ll either need to cross compile your binaries, or just compile them natively on the device itself. Compiling on the device works fine as long as you have the relevant packages, however if I was going to build a 2.6 kernel, I’d rather do it on an x86 quad core intel host, rather than waiting a week for the device to do it. I also wanted to minimize the writes on the CF card.

OpenWrt comes with a nice buildroot environment which you can read about and download from www.openwrt.org using Subversion.

Here http://downloads.openwrt.org/kamikaze/docs/openwrt.html#x1-310002 is a great HOWTO on getting the build root environment set up on your x86 host.

Also, see: http://wiki.mikrotik.com/wiki/RB500_Linux_SDK – this is a very complete HOWTO, which is why I’ve not covered most of the installation process and just detailed customizations.

You’ll need to select the RB5xx target for the kernel. Also, run:

In your build root top directory, and add USB support (as my one is modded for USB which is not RB5xx default.

While you’re there, browse to the networking options and make sure you have everything you want, specifically the schedulers for traffic shaping.

Here is my precompiled image:

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Tags: /dev/cfa1, /dev/cfa2, /dev/cfa3, bridge, build root, buildroot, debian, dropbear, ifconfig, iptables, kamikaze, mikrotik, miniupnp, miniupnpd, mips 4kc, multiple isps, multiple providers, ntp, ntp client, openwrt, precompiled image, rb532a, rbxxx, split route, subversion, svn kernel, uplink, usb, usb support, x86