JTAG ICE mkII

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Hi all ,

I am new to AVRs and am designing circuit for a board. My question for
ppl experienced with AVR and JTAG ICE mkII are -

1) Can JTAG ICE mk II be used for emulation as well as In-Circuit
programming ?

2) Are there any special considerations for circuitry of the target
board to use JTAG ICE mkII for both ISP and Emulation?

BR
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Re: JTAG ICE mkII

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Yes, but it's hardly stable.

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Yes: be prepared for frustration. Wire your board exactly like the
Butterfly. Don't use the multiplexed JTAG I/Os for anything else. Be
prepared for a lot of weird stuff with order of powering things up and
plugging things in. Be prepared to lose contact with the debugger
randomly in the middle of a debug session.

I don't even bother any more. I use an AVRISP mk2 to program the chip
and debug the old-fashioned way, with a scope, LEDs, RS232 etc.


Re: JTAG ICE mkII
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And slow.  It takes forever to step through codes.

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Yes, include both interfaces.

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I use an ARM for ISP programs and JTAG boundary scans.


Re: JTAG ICE mkII
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Have you written code for ISP commands on the ARM ? or are you using
open source code ? Have you built an ISP?

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I am using  ATMEGA2560 , it has three lines for serial programming -
PDI , PDO and SCK plus the reset , can I use the AVRISP mk2 to
programme it (using the 6 pin header)?  Stupid Question I think , but
worth asking as I dont have any experience on AVRs

Thanks Again

BR
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Re: JTAG ICE mkII
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Probably the same: MOSI(PDI), MISO(PDO), SCK, RESET, VCC & GND.

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Re: JTAG ICE mkII
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I second that. Put connectors on your board for both ISP and JTAG as
there are things one can do the other can not.

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The ISP pins are mostly independent of the JTAG pins. You can program
via JTAG, you can program via ISP. The CPU config flags in EEPROM can
disable JTAG and then only be reached from ISP. With JTAG enabled they
can be reached from JTAG but you could screw up and lock yourself out.

IIRC the JTAGICE mkII does not do ISP. The ISP mkII costs all of $35.91,
cheap enough that you should not skip it when buying a JTAGICE mkII.

As for the 6 pin ISP header, there is an alternate pinout for 10 pins.
Easier to buy 10 pin cable connectors than 6 if it bothers you to plug a
10 pin cable into a 6 pin header. Biggest problem in using 10 pins for
ISP is that the header looks same as a JTAG header to production line
workers.

The original ISP mkI came with both 6 and 10 pin cables. The 10 pin was
not a compatible pinout with the 6.

Double check, and triple check, your pinouts for ISP and JTAG as they
connect to different pins on different AVRs. The ATmega64 tripped me the
first time as the JTAG documentation named a particular pin function for
each pin in the header but there was one line 100 or 200 pages into the
datasheet that said, "Oh by the way the JTAG for this AVR connects to
these pins rather than those pins used on other AVRs."

Others have mentioned debug sessions on JTAG may run away and require
your target and JTAG be power cycled in the correct order to recover.
What I have seen is that this is somehow related to the target board but
have never figured out why one design works better than others. Happens
with JTAGICE, JTAGICE mkII, Dragon, and 3rd party JTAG. I have not had
similar problems using DebugWire. DebugWire is only available on smaller
parts where JTAG is not available.

Re: JTAG ICE mkII
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Hi all ,
Thanks so much for clearing all this out , I have a much better
understanding of JTAG and ISP from this discussion.
Now I will go and burn the data sheet with my eyes!

Cheers
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Re: JTAG ICE mkII
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Updated my Dragon yesterday to AVR Studio 4.13 Service Pack Build 557
and didn't have the kinds of problems I have had recently with the Dragon.

Wasn't emulating so much as I was only enabling a pin on PORTC and
toggling its output while playing with the hardware connected. A time or
two AVR Studio claimed to be changing the output bit, but it didn't
change on the hardware. Always stuck high if that means anything to anyone.

A power cycle on target and Dragon regained control.

Should point out that static discharges are very likely when fonding
hardware like this, whether or not I noticed, no matter the precautions.
System seems to set for hours without problems, only requires power
cycle reset when I'm poking on it.

Re: JTAG ICE mkII

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The real question is: what does it do if locked in a sealed box with a
vial of prussic acid?


Re: JTAG ICE mkII

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The spec sheet says it can do ISP but doesn't come with an ISP cable.

Eric


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