RE: [avr-gcc-list] Target connecting problem with JTAGICE mkII

[Eric Fu]

Graham Wrote:
  
> Eric,
> 
> This isn't really about AVR GCC is it?
> 
> Anyway, I can't see anything obviously wrong with what you're doing.
As I
> make and sell an ICE interface (the AVR "ICE-Cube") there is
information
> on
> my Web site that might be useful to you, including a bit of trouble
> shooting
> stuff.
> 
> Assuming you didn't damage the ATmega16, I would suggest you check for
> something else connected to the same GPIO pins as the JTAG interface
uses.
> 
> The JTAGEN fuse is programmed on all Atmel MCUs when they leave the
> factory,
> so unless you cleared it, this isn't the problem.  AVR Studio and the
JTAG
> ICE will manage switching between programming and OCD for you.  You
can
> leave the OCDEN fuse unprogrammed and it will be programmed and
cleared as
> needed.
> 
> What about clock speed?  The JTAG interface cannot run faster than one
> quarter of the MCU clock rate.  What is it set at?  Is your target
> clocking
> the MCU slower than the STK500?  This shouldn't affect the initial
startup
> of the JTAG ICE, however, as it doesn't need the clock at all to read
the
> JTAG ID.
> 
> If none of this helps, maybe you could clarify "JTAGICE mkII failed to
> detect the target".  Is this what appears in a pop up or is it your
own
> description of the problem?
> 
> Graham.
> http://www.ecrostech.com
> 

[Eric Fu] 
You are right Graham. I realized that after I sent it out. However, so
far I've only got your kindly help 'accidentally', I didn't get any help
from else where, which is supposed to be more appropriate.

The good thing is JTAGICE mkII can now detect my target, load and run
the code, although the code doesn't do what it used to do on STK500. I
still couldn't find out what caused it initially. It could be the
intermittent power supply connection. I'm using the external crystal
option. But there is no oscillation measurable at XTAL1 /XTAL2 pins. I
will check what causes it. 
By the way, "JTAGICE mkII failed to detect the target" is what appears
in the pop-up.

Thanks a lot for help.

Eric Fu