AVR-Chat

----- Original Message -----
From: "Larry Barello" <yahoo@barello.net>
To: <AVR-Chat@yahoogroups.com>
Sent: Saturday, November 06, 2004 5:36 PM
Subject: RE: [AVR-Chat] Fuse gotchas (was Re: STK500 starter kit)


>
> No AVR part is useless after programming the fuse bits.  You just have to
> use the appropriate programming method - fortunately the STK500 supports
> both ISP and Parallel programming.  For example, program the RESET line to
> be an I/O pin on the tiny26 and you are REALLY HOSED, unless you use
> parallel mode to "recover" your chip.  However, for the run of the mill: I
> programmed an external clock...  You simply enable the external clock
drive
> on your STK500 - read the manual about those little jumpers near the back
of
> the board.
>
> There are gotcha's with ISP: if your target board has an output driving
the
> MISO or SCK then it won't work.  I arrange my designs to have the ISP
lines
> brought directly out to the header and then insert 4.7k resisters between
> the ISP pins and the rest of the circuit.  I just don't put any high-drive
> elements on the other side of the resisters (e.g. LEDs)
>
> Cheers!
>
> -----Original Message-----
> From: Ian Drennan [mailto:ianid@sai.co.za]
> Sent: Saturday, November 06, 2004 6:03 AM
> To: AVR-Chat@yahoogroups.com
> Subject: Re: [AVR-Chat] Fuse gotchas (was Re: STK500 starter kit)
>
>
>
>
> > I agree that this is an issue for beginners and more attention should
> > be brought to it.
> >
> > Recall that I discovered that fuse gotchas are solved for AVRs with
> > the JTAG interface because this interface does not require the clock
> > to be running so you can repair any fuse misconfigurations.
>
> Greetings all
>
> I have been following this thread with  interest as I am new to AVR and am
> about 3 weeks into using my new STK500.
> The 'fuse gotcha' issue seems to have got me today when I plugged in a new
> Mega8 and changed an oscillator fuse so as to run using the STK500 onboard
> clock. I set the fuse for external clock i.e.. Ext. Clock; StartupTime:
6CK
> + 64 ms;[CKSEL = 0000 SUT = 10]
>
> Obviously this was a mistake as I am now locked out and assume the part is
> now useless. Please can someone advise what the fuse setting should have
> been to allow the mega8 to run using the STK500 onboard clock.
>
> Many thanks
> Ian

Larry
Thanks for this reply.
Soon after sending my mail I realised that the I had the OSCSEL jumper miss
mounted. All is now ok
Regards
Ian