Pramode C.E - The GnuVision Blog

Play! framework + BeagleBone workshop at NSS Engineering College

2011-12-21T00:00:00+00:00

Play! framework + BeagleBone workshop at NSS Engineering College

Dec 21, 2011

I was at the NSS Engineering College, Palakkad on the 20th (at the invitation of "ABACUS", the association of CS tudents of the college) to conduct a workshop on the broad topic of "do something fun with GNU/Linux". The audience was a bunch of 6th semester CS students with very little exposure to GNU/Linux. My plan was to show them how to develop a small web-app which will interact with some Python code running on the BeagleBone. This was going to be my first public demonstration of the amazing Play! framework as well as the lovely BeagleBone.

As there were students in the audience who did not even have exposure to HTML, I started with a quick intro to HTML and then explained the basics of the HTTP protocol, how does a web client interact with a web server and stuff like that. This was followed by an introduction to Play. I didn't get enough time to explain the working of some Python code I had written for the BeagleBone (the code simply turns LED's ON/OFF) - so, I had to be content with just giving a demo of the final program which lets you turn ON/OFF the LED's on the BeagleBone through a web interface.

The surprising thing for me was the very low level of awareness about GNU/Linux among the students. The college CS labs still seem to be using primitive stuff like Turbo-C and the only notion students have of an "IDE" is the Windows Notepad!! Hopefully, things will now change for the better, as there are some students who are taking the initiative to bring more FOSS awareness.

Python workshop at ASIET

2011-09-23T00:00:00+00:00

Python workshop at ASIET, Kaladi

Sep 23, 2011

Conducted a Python workshop yesterday for the IEEE student branch of ASIET (Adishankara Institute of Engineering and Technology, Kaladi). I had a chance to demonstrate a simple LED "magic trick" using the EzChronos and MSP Launchpad!

Getting started with MSP430 Launchpad on Debian

2011-09-18T00:00:00+00:00

Getting started with MSP430 Launchpad on Debian

Sep 18, 2011

I am trying to get some demos running with an EzChronos and a couple of MSP430 Launchpad's. Here is a brief outline of the steps required to get your first "hello,world" running.

I had installed the MSP430 toolchain on a few machines sometimes back. The procedure was simple - pull out a set of scripts/patches from here and run one of the supplied scripts - this takes care of getting the core components - binutils, libc and gcc, applying the patches and building them. The procedure was painless. But it seems that the developers have abandoned this approach - the procedure to build the latest version (msp430-gcc version 4.5.3) is to download all the core components, apply the patches and do the build manually. This takes a bit more effort. Here is a document describing the process.

I was doing the build on Debian Squeeze - everything worked fine except when it came to building gcc. The version of GCC that was being compiled required newer versions of three libraries - gmp, mpfr, and mpc. The sources for these three libraries had to be downloaded and built following the instructions given here. Also, gdb ver 7.2 was not avaible - but ver 7.2a worked fine.

There is an excellent tool called mspdebug which can be used for flashing the MSP430G2231 on the launchpad and also for debugging.

Once the toolchain and "mspdebug" are built properly, we can write our "hello,world" program - lighting up an LED connected to P1.0 of the processor:

#include 
main() 
{
   WDTCTL = WDTPW + WDTHOLD;
   P1DIR = 1; P1OUT = 1;
}

The first line is for disabling the watchdog - a compile time option, "-mdisable-watchdog" can be used to do this in the C library startup code itself.

Compile the code with:

msp430-gcc -mmcu=msp430g2231 led.c

Flashing is done by invoking "mspdebug rf2500" and executing the commands:

erase
prog a.out