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Re: [avr-gcc-list] ATMega128 pcb, startup problem...

From: Torsten Mohr
Subject: Re: [avr-gcc-list] ATMega128 pcb, startup problem...
Date: Wed, 1 Jun 2005 21:32:59 +0200
User-agent: KMail/1.8


> > MOSI, Pin 12 is logically connected to parallel port "D0"
> > MISO, Pin 13 is logically connected to parallel port "Busy" and
> > "Sel.In". SCK, Pin 11 is logically connected to parallel port
> > "Strobe". PEN, Pin 1 is at GND level.
> Here is where the mistake seems to be. On the mega128 the ISP pins do
> not correspond to the SPI pins. In fact the ISP DI and DO pins are
> connected to pins 2 and 3 which are the UART0 pins.

that was exactly the problem, thanks !!!

Still i wonder why uisp finds a device "similar to ATmega103-old".  After 
power-up a ATmega128 is correctly detected, but after that only an 
ATmega103-old.  This happens even if i only type "uisp -dprog=dapa" without 
any other command.

So for every command "uisp ..." i type i need to disconnect the device from 
power and reconnect it.

I have a pcb for proper output levels attached to the parallel port, so the 
parallel port outputs are routed into this pcb which ensures proper voltage 
levels and then outputs these to the target.
The RESET output level of that pcb is routed directly into the RESET input of 
the target and there are no additional capacitors.

Is this maybe a problem?

I tested "uisp --erase" followed by "uisp --upload ..." on an old AT2343 
without problems.  Here i don't need to disconnect the power.

Is there something i can do to always detect an ATmega128?

Best regards,

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