AVR-Chat

>>> dvanhorn@dvanhorn.org 05/11/2004 12:15:00 pm >>>
>Not everyone wants to flash LEDs on a development board, and IMHO
Atmel made
>a mistake by pushing the STK500 as their base level programming
solution.
>
>There's always the AVRISP. No good for Tiny-11's or anything else that

>needs parallel programming, but otherwise, just fine.

Until you accidently "disable" the ISP mode which renders your chip
next to useless unless you have a parallel programmer to fix it. For
some reason people don't like to talk much about this major trap for
young players.

I have both the AVRISP and STK500, and use the AVRISP where possible
because most of my development is done with the chip on my actual target
board.
The STK500 also has ISP mode as well, but the AVRISP is just so much
neater.

Dave :)

--- In AVR-Chat@yahoogroups.com, "David Jones" <david.jones@s...> 
wrote:
> I have both the AVRISP and STK500, and use the AVRISP where possible
> because most of my development is done with the chip on my actual
> target board.

You can build an AVR910-compatible ISP programmer pretty simply using 
either an AT90S1200 or AT90S2313 (see the URL below).  Of course, you 
need a programmer of some type to program the AVR used in the 
programmer.

I built the 2313-based device and it serves quite well.

AVR910 ISP programmer:
http://www.serasidis.gr/circuits/avr_isp/avr_isp.htm

The AVR910 nomenclature derives from the Atmel application note 
describing the ISP procedure, available here:
http://www.atmel.com/dyn/resources/prod_documents/DOC0943.PDF

>
>Until you accidently "disable" the ISP mode which renders your chip
>next to useless unless you have a parallel programmer to fix it. For
>some reason people don't like to talk much about this major trap for
>young players.

I wouldn't say that so much as it just dosen't happen that often.

I also have the STK-500 and AVRISPs, both are useful.

Try a PIC sometime, IIRC if you lock the code, you can no longer reprogram 
the part at all.
On the AVR, you just erase the part and carry on.


You do have to make sure that the programmer isn't running too fast for the 
target system, especially when working with <1 MHz clocks.

At 03:16 AM 5/11/04 -0000, you wrote:
>You can build an AVR910-compatible ISP programmer pretty simply using 
>either an AT90S1200 or AT90S2313 (see the URL below).  Of course, you 
>need a programmer of some type to program the AVR used in the 
>programmer.
>

By the way I have just programmed an ATmega8535 with the above and
version 3.0 firmware using the Mega8515 settings (including compatibility
fuse)
and it seems to work well. For those not aware AVRprog has no support for
the mega8535 so I took the chance and it worked. I tried other devices without
success but both of the chips above are very similar so it should work.

Regards

John Samperi

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