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AVRISP-II and AVRDUDE

Posted: Thu Mar 12, 2015 2:44 pm
by MikeB
I use an AVRISP-II programmer for flashing Atmel AVR processors, but I couldn't use it with eepe as Atmel Studio 6.0 loads its own drivers that don't work with AVRDUDE.

I just found this site however:
http://www.visualmicro.com/post/2014/01 ... duino.aspx

and, having followed the instructions, I now have the AVRISP-II working with AVRDUDE and eepe.

There is one other problem with using the AVRISP-II, the same problem I have with my STK500. The signal drivers cannot cope with the capacitors that load the reset and signal lines. I solved this for the STK500 by buffering the programmer output signals with some 74AC devices. These provide plenty of drive and I use this with both the STK500 and the AVRISP-II.

Mike.

Re: AVRISP-II and AVRDUDE

Posted: Fri Mar 02, 2018 10:16 pm
by Escrich
Hi Mike, which IC have you used as buffer?
As we discussed latest days I have this same problem, and simply I whan't to know if you used buffers, or nor or nand gates, just to go directly and not to waste time.
Thanks for all of your help

Re: AVRISP-II and AVRDUDE

Posted: Fri Mar 02, 2018 10:53 pm
by MikeB
I believe I used a 74AC04 device, with the gates used in pairs to provide a non-inverting buffer on each of RESET, SCK and MOSI.

Mike

Re: AVRISP-II and AVRDUDE

Posted: Sat Mar 03, 2018 9:45 pm
by Escrich
Then i can understand that MISO is a bidirectional signal, am i right?

Re: AVRISP-II and AVRDUDE

Posted: Sat Mar 03, 2018 10:21 pm
by MikeB
No, MISO is data from the AVR processor to the programmer (Master In Slave Out).

Mike

Re: AVRISP-II and AVRDUDE

Posted: Sat Mar 03, 2018 11:21 pm
by Escrich
Here you, and whoever have something that could help.
Buffer PCB.rar
Circuit and pcb design for buffer
(58.24 KiB) Downloaded 438 times
Thanks a lot for your help

Re: AVRISP-II and AVRDUDE

Posted: Sun Mar 04, 2018 11:56 am
by jhsa
MikeB wrote: Fri Mar 02, 2018 10:53 pm I believe I used a 74AC04 device, with the gates used in pairs to provide a non-inverting buffer on each of RESET, SCK and MOSI.

Mike
Mike, wouldn't a CD4069 do the job? I think it might be easier to find and probably cheaper?

João

Re: AVRISP-II and AVRDUDE

Posted: Sun Mar 04, 2018 3:28 pm
by MikeB
Unlikely! The point of this buffering is to use a high current output drive, the '4069 only drives 1mA at 5V, the 74AC devices drive 24mA.

Mike

Re: AVRISP-II and AVRDUDE

Posted: Sun Mar 04, 2018 3:42 pm
by jhsa
Understood. Thanks for the explanation..

João