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Re: [AVR-Chat] JTAG problems with ATmega164P

Re: [AVR-Chat] JTAG problems with ATmega164P

2009-10-16 by John Samperi

At 11:22 PM 16/10/2009, you wrote:
>Anyone have this type of problem ?

I must have been about the first person to find this
bug when the Dragon first came out. Same thing, old JTAG
worked with 300mm cable, the Dragon did not, Some older
chips worked with longer cable, Mega164 and family did not.

June 2007 thread about this here:
http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=50664

Atmel support did not have an answer and I stumbled
across the same solution of keeping the JTAG cable
between 100-150mm.

Interesting about the 1K pull-up. I always use a 4K7
pull-up on the reset line when using DW, the recommended
max is 10K, without problems, apart from the usual Dragon
tantrums.

Regards

John Samperi

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