Archive for December 2009

Getting Started With The Atmel AVR Processor

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It has been a while since I worked on the Atmel AVR line of microcontrollers.   Things have changed since I last played around with them.  I did some digging to figure out how to start up again so here is a quick guide for those that are looking.

Step 1:

Pick a Atmel AVR MCU that fits your requirements. I’m doing a simple project so I picked the ATtiny26.

Step 2:

Buy, beg, borrow, or steal a AVR ISP a.k.a as the AVR In-System Programmer. There are schematics for home made programmers out there, I’ve had problems with bad solder joints and messed up connections with home made programmers so I avoid them.  Debugging is hard enough, a bad programmer is a problem you really don’t want to debug.

Step 3:

Wire up your AVR processor to the AVR ISP using the documentation provided with the ISP.  It is a matter of wiring up the MISO, MOSI, SCK, Reset, Vcc, and Ground pins and should take only a few minutes on a breadboard.

Step 4:

Now, on to the software.  Download and install WinAVR.  WinAVR  is a set of utilities that includes a port of GCC to the AVR family, AVR-GCC, and several helpful Unix utilities.

Step 5:

The last step is to to  download and install AVR Studio 4.  Get the latest version.  AVR Studio 4 has been updated to integrate with AVR GCC, you type your code in using C.  It generates the makefile needed to compile your code with AVR GCC and, if you are using the AVR ISP, will let you upload your code directly to your microcontroller.

To get started, start up AVR Studio and select ‘New Project.’  Select ‘AVR GCC’ as the project type and click Next.

Then, select your microcontroller and the debug platform.

I haven’t made significant progress on my ATTiny26 code, but if you wish, you can select the ATMega32 microcontroller/AVR Simulator and try out the code from my Binary Clock.

The debugger is pretty cool, besides stepping through the code, you can also view register states and modify variables on the fly.

Enjoy 🙂

Written by M Kapoor

December 24, 2009 at 5:53 am

Posted in microcontrollers

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Railsplayground 1 1/2 year review

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I wrote a review about Railsplayground about 1 1/2 years ago.  I’m writing this as a follow-up to my last review since I’ve noticed that there are very few long term reviews for webhosts our there. I was very interested in Ruby and Rails when I first signed up with Railsplayground. Since then I have lost interest in Ruby for various reasons. Despite my loss of interest in Ruby, I kept my Railsplayground account.

They have been a great host over the last 1 1/2 year and I’ve had no problem with uptime or resources. My cron jobs always run on time and I’ve never had any complaints about being unable to download files. I now use then to host pictures and files I want to share with others. I’ve also set up s3sync so I can easily transfer files to and from my backups in Amazon AWS from within my Railsplayground shell account.

Besides Ruby, they also have great support for Perl.  I’ve written several perl scripts and run them reguarly via cron, no problems there either.

My only complaint is that despite the fact that hard-drive space is getting cheaper, they have not increased their account quotas.  I am still at their base $5/month plan and am stuck with 3GB of storage – the same amount that I started with more than 18 months ago.  In addition, the storage space they offer for their source control hosting has been dropping.  They started out offering 1GB of SVN hosting when I first started, this later dropped to 200MB, and is now down to 100MB. This is very developer un-friendly trend from a developer friendly host.

In terms of value, I feel that Railsplayground is still a fair deal.  They have great customer support and respond in minutes whenever I have a question.  However, VPS prices are at the point you can get a small VPS, be your own boss and run whatever you feel for about the same price or a couple bucks more.

Written by M Kapoor

December 22, 2009 at 2:34 am

Posted in review

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