Sonsivri

Need you help
im normaly program my atmega with WinAVR
and paralelle program port
this one is work very fine to program the chip
some time a make one mistek and program wrong fuses bits in atmega
this is not a problem because im reprogram with my other programer (unlooper)
and a external clock and put the wrong fuses back

but a want to make a new project to a very simple programer
with a external clock with a nee555 to the clock of atmega
together the paralell port
i have make a design with proteus
but my problem is that i am not good electronic
and i wil like to now if you can have a look to my design
and tel me if is the right design or y make some misteck

sorry for my bad inglish
Belgitaes

http://rapidshare.com/files/319720262/New_Project_With_Nee555_For_Wr

Ummm the Link you post is corrupt.

So you made a new more simple programmer for AVR?
It has an NE555 as clock (to change the frequency ?) and uses the parallelpor too. Am I right ?

Why don't you use a RS232 or better a USB programmer ? There are many projects around
with very easy schematics. It's because the parallel port dies. No newer computer has one.
If you build an easy RS232 programmer you can use a RS232-USB converter to connect it to
almost every computer.

However. Please post the full link and/or maybe you can send me a picture of
the schematics instead becaus I have no proteus. I'm sorry :)

Just curuios but why don't you ?

Sorry For the link i upload again schematic with proteus
 
http://rapidshare.com/files/320161242/New_Project_With_Nee555_For_Wrong_Fuses_Bit_In_Atmega.rar.html

and on this page the picture of the schematic

http://img94.imageshack.us/img94/4386/81211400.jpg

http://img526.imageshack.us/img526/2008/prog20atmega8820casero1.jpg

http://img687.imageshack.us/img687/3171/nuevoprojecto.png

Thank you

It's because I use EAGLE and I don't want 100 different editors on my PC :)

Posted on: December 14, 2009, 00:41:29 - Automerged

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Thank you Belgitaes for uploading.

Most parts of the schmeatic are ok but there are some mistakes (have a look at my attachment "schematic_2").

You don't need the resistor array with the capacitor if you have external power supply.
Next is the circuit of the crystal. It's a little bit confusing but I' sure it won't work that
way. Ant the last one is that I son't know whether the ATmega88 works with 48Hz clock
(produced by the 555 timer). Maybe make it variable (10Hz-10kHz) with a trimmer.

I think he is tring to power programmer from printer port, and got it wrong.
As to using the 555 and crystal without any ajustment pot, your timing is set by choice of crytal, and I think using a 40xxx gate is the better option, you will find loads of samples on how to trim frequency will google.