AVR Programming 02: The Hardware

You may be able to write the most eloquent code in the history of embedded systems but without a way to run it on the hardware it will be worthless. In this installment of the tutorial series we will:

  • Look at some of the available AVR programmer options
  • Place the microcontroller on a breadboard and connect it to a power supply and a programmer.
  • Use programming software to send some example code to the microcontroller

If you missed Part 1 take a few minutes to review that portion of the tutorial and then join us after the break.

Series roadmap:

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USBasp: AVR programmer based on ATmega8

We love our AVR Dragon programmer but it can be nice to have a cheap and simple in system programmer on hand too. The USBasp is one such programmer that uses and ATmega8 as its only IC. It requires just a handful of components and can be purchased as a kit, or etched and assembled at home. If you source your own parts the chip does need to be programmed which makes for a chicken-or-egg scenario. We’ve used the Parallel-port dongle (schematic) from Adafruit’s Spoke POV before. It’s basically just a DAPA cable and a few resistors, a ribbon cable (use and old IDE cable if you have to) and a parallel port connector can have you up and running in no time. This is also a great way to get a friend into working with embedded systems. Order parts for a few of these and give them away to your buddies.

AVR Dragon wiring alternative

dragon_jumper_board

We love our AVR Dragon programmer. It is a small board with a lot of functionality: in-circuit serial programming, JTAG, debug wire, and high voltage serial programming. Unfortunately, out of the box it is not quite ready for action. The Dragon ships with an unpopulated prototyping area and missing a pin header for the HVSP. For most people this means soldering on pin headers and a ZIF socket then jumpering between the various programming headers and the header for the socket. Tired of working with jumper wires, [Jussi] designed a small PCB to make the connections (original link in Finnish). [Read more...]

How to write udev rules

writing_udev_rules

Since the adoption of Kernel 2.6, Linux has used the udev system to handle devices such as USB connected peripherals. If you want to change the behavior when you plug something into a USB port, this section is for you. As an example, we will use a USB thumb drive but these methods should translate to any device handled by udev. As a goal for this exercise we decided to create a symlink and execute a script when a specific thumb drive was loaded. The operating system we used for this exercise is Ubuntu 9.04 Jaunty Jackalope. [Read more...]