AVR Drivers: Difference between revisions

Some drivers have an Atmel microprocessor on board to control different modes. Atmel processors are programmable therefore the same driver can be loaded with different settings to give different numbers of modes, different output levels, as well as flashing modes like strobe or SOS, along with features like mode memory. This page will summarize some of the things you will need if you want to program your own drivers. This is based on a [http://budgetlightforum.cz.cc/node/799 Budget Light Forum discussion thread] where you can go for help or to get answers to your questions. This whole thing was started by a BLF member Tido.

Of course you will need a driver first. There are several NANJG drivers available that include an Atmel TINY13A chip that can be programmed. These chips can also be locked down so they can't be changed, but so far none seem to be. However, some variants of NANJG drivers use a PIC chip that can not be programmed with AVR tools. See [[Popular drivers]] to see some of the drivers people have been using. Most of these use current regulators to limit the current delivered to the LED while the Atmel chip itself turns the power on and off very quickly, leaving it on for full power, or flashing on and off quickly to simulate a lower mode. This is called Pulse Width Modulation (PWM). By slowing the flashing more, you get strobe modes or SOS modes. So essentially the Atmel chip is just a computer-controlled on-off switch.

You will at least need AVRDUDE (AVR Downloader UploaDEr) to upload and download files to the Atmel chip. It is a command line interface (DOS). If you use Tido's programs then you don't need to compile anything. Those programs are ready to be loaded.

If you want to customize the programs or write your own, you will need a compiler. The programs can be written in assembly language or C. Assembly can give more compact programs, but C is easier to write and understand, so that is what is being used so far. AVR Studio is available from Atmel to allow you to write and compile programs and load them. [http://winavr.sourceforge.net/ WinAVR] is a collection of all the software you need as well as a graphical user interface (GUI) to edit, compile, and load programs. Eclipse is another package that can be used to develop programming and is what Tido uses.

So Wire 1 (MOSI) of the ribbon cable from the programmer must attach to Pin 5 of the Atmel. Make sure you mark which end of the clip attaches to the top of the Atmel or everything will be misaligned next time you use it. Line up RST and SCK with their appropriate wires. But notice that MISO on the programmer is Wire number 9 and the ribbon only has 8 wires. You will need to disassemble the end of the ribbon cable at the controller end and move wire 8 over to the 9 position so that MISO lines up correctly.