[En-Nut-Discussion] Problem connecting analog sound on port F

[Henrik Maier]

If you have a device which can only be programmed with JTAG then you must
not touch the JTAG fuse bit as it renders the device not being programmable
afterwards. You turned off the programming feature forever. This is not
desirable in most situations.

If your device is programmed using SPI/ISP, then the JTAG can be disabled
safely using the fuse bit.

More info can be found in the ATMega128 data sheet which I recommend to
consult always before changing any fuse bits. It always a good idea to learn
about the consequences of sometimes irreversible actions.

Henrik
http://www.proconx.com

> -----Original Message-----
> From: en-nut-discussion-bounces at egnite.de [mailto:en-nut-discussion-
> bounces at egnite.de] On Behalf Of jakub nowak
> Sent: Wednesday, 12 March 2008 11:00 PM
> To: Ethernut User Chat (English)
> Subject: Re: [En-Nut-Discussion] Problem connecting analog sound on port F
> 
> For me there is no difference to change a fuse bit or registry. I
> don't have any JTAG, I don't use debug, I want to use atmega128 as
> atmega128 I don't need compatibility with atmega103. I know that if
> You have JTAG better will be to change this by software but try by
> hardware(manualy fusebits). I think that only risk changing fuse bits
> is when You program with JTAG and You will turn him off or when You
> change to wrong values fuses connected with oscilator.
> 
> 2008/3/12, Vincent Timmerman <vincenttimmerman at gmail.com>:
> > I tried it out with a disabled JTAG fuse, and it works. There is still
> much
> >  noise on my audio, but at least i hear it. I'll check the noise
> reduction
> >  first to see if there's room for improvement.
> >
> >  Thanks for the tip!
> >
> >
> >  Vincent
> >