Re: [avrdude-dev] JTAGICEII on CAN128

[Odd Arild Olsen]

On Friday 30 June 2006 17:44, Colin O'Flynn wrote:
> Hello,
>
> Did some more testing, using my MK-II and AVRStudio.
>
> The JTAG interface did not work at first. However when I told AVRStudio to
> use the external reset pin to hold the device in reset, it worked fine.
>
> Do you accidently set the JTD bit in the MCUCR? That would disable the JTAG
> and explain the behaviour you are seeing...

A good idea, but I don't think so. All I did to transfer the program to 
mega128 was to change prescaler bits, switch counters 0 and 2. I tend to not 
use pointers, so it's not probable that I have written accidently over the 
MCUCR. And that would have had the same effects for the mega128, the 
JTD/MCUCR have the same address in both chips. I also think I tried the 
external reset trick when in AVRStudio.

I actually connected my AVRISP to the CAN device while it was still sitting on 
the PCB. However, I intstalled AVR studio 4, and was urged to download a new 
firmware version, task ended without success. So my ISP-programmer went into 
coma.

Today I manually got the programmer firmware correctly updated. I tried to 
reprogram an old card with a mega8535 via the ISP, worked fine from 
AVRStudio. But when I rebooted and tried to program under Linux there was no 
contact with the programmer. (The makefile use uisp and not avrdude). I found 
an old version of the STK500 firmware and reprogrammed again in AVRStudio. 
Now I could not connect to my controller. I went back to Linux and uisp now 
worked fine. 

The newer AVRStudio obviously use a modified protocol with the AVRISP/STK500.

Now, I remember that AVRStudio also downloaded a firmware update to my 
JTAG-programmer. Can the origin of my problem be some small protocol change 
that avrdude has not adopted to yet?
 
regards
OAO

>
> I'm not sure if avrdude can use the external reset line to do the same
> thing AVRStudio does, I haven't played around with avrdude's JTAG
> programming much.
>
>  Regards,
>
>   -Colin