AVR-Chat

etgfx wrote:
> Greetings,
>
> Does anyone know what the best way to start out in AVR programming
> is?  I've heard from a local hobbiest programmer that there was a way
> to do a 6wire parralel port programmer, but I wasn't able to find
> this from google.  Does anyone have a link to this, or other simple
> programmers?   There doesn't seem to be a whole lot out there for the
> student budget that I have been able to find.  Also any other advice
> for begining avr programmers would be very appreciated.
>
> -
> Michael Haisley

You have the option for the AVRXS small package. It is a DOS software to
transfer the program to your AVR, and a simple DB25 connector to your PC
parallel port, 4 resistor and 5 wires to your AVR, that's all.

Check it out at http://www.ustr.net  AVR files - look for AVRXS.ZIP,
FF378.EXE and FF278.EXE.

The AVRXS original function was to program an AVR into an isolated board,
but you can use it to program the chip into the working board, no problem.
The only issue done by the original software writer was that he kept the
RESET line active after programming, as you would remove the chip from the
programmer socket and move to the working board, it was ok, but if you
program the chip at the working board, the parallel port will keep the chip
in reset state after programming, so your board will not run.  I build the
FF378 and FF278 small DOS programs to set the parallel port (FF378 for LPT1
and FF278 to LPT2), so after programming you just run one of those, and the
RESET line of the AVR will be free and the program will run at the working
board.

That is a pretty easy, low cost and nice solution for starters. Later on
you can move to a bigger and expensive solution, if you want... :)

The MISO, SCK and MOSI pins of the AVR should be kept only for this
communication, if not, programming failure CAN happens.  There is a
solution for that, provided by a friend from Brazil, that incorporated a
74LS374 to the circuit, activated by the RESET coming from the Parallel
port, so, the Parallel port information does not get to the MISO, MOSI and
SCK pins after RESET is freed, then you can use those pins at your project
without any interference of the Parallel port. If and when you need to use
ALL the pins of the AVR, please ask and I will give you the directions.

Ok, there is a bunch of other solutions available, it is up to you to
choose the one you will use, and by the way, it is so cheap that doesn't
hurt to try ALL of them.

Personal recommendation:
Start learning the AVR by the right (and only) way:

ASSEMBLY LANGUAGE!!!

Wagner Lipnharski - email:  wagner@ustr.net
UST Research Inc. - Development Director
http://www.ustr.net - Orlando Florida 32837
Licensed Consultant Atmel AVR _/_/_/_/_/_/