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avrdudes / avarice

AVaRICE is a program for interfacing the Atmel JTAG ICE to GDB to allow users to debug their embedded AVR target.
GNU General Public License v2.0
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[bug #10] jtag daisy chain bits limitations #10

Closed avrs-admin closed 2 years ago

avrs-admin commented 2 years ago

guerrier 2008-01-11 06:54:03

Hello

the limitations on the daisy chain parameters ( -c x,x,x,x option ) seem to be wrong. my guess is 255 for all four, or 7,7,255,255 instead of 255,255,7,7

i had this problem on a board with 2 devices and total 13 bits after the AVR.

I could not try to recompile without the limitation, because the nightly snapshot or release archive seem to be broken (or it is my tar which is broken ...)

http://avarice.cvs.sourceforge.net/avarice/avarice/src/main.cc?revision=1.40&view=markup

if (units_before > 255 || units_after > 255 || bits_before > 7 || bits_after > 7) {

This issue was migrated from https://sourceforge.net/p/avarice/bugs/10/

avrs-admin commented 2 years ago

joerg_wunsch 2008-01-11 12:43:07

Logged In: YES user_id=1097648 Originator: NO

The actual limitation is unfortunately not documented in AVR067 but instead well hidden in the JTAG ICE mkII manual which only ships in CHM format as part of the AVR Studio help files. A maximum of 32 bits before and 32 bits after is supported. Due to the nature of JTAG daisy-chaining, this implies at most as many units before and units after as there are bits (usually much less units than bits though).

avrs-admin commented 2 years ago

guerrier 2008-01-12 09:01:58

Logged In: YES user_id=1977888 Originator: YES

okay for 32 bits on MKII, but other programmer probably have other limits. I have a MKI clone, and other people have the new dragon ( don't know if it supports chaining, i hope it does ....)

avrs-admin commented 2 years ago

joerg_wunsch 2008-01-12 21:03:08

Logged In: YES user_id=1097648 Originator: NO

I've already checked the mkI documentation before, it mentions the same limitation to 32 bits before/after. (All the clones are running the Atmel mkI firmware, so should be the same.)

The AVR Dragon manual doesn't mention JTAG daisy-chaining at all. However, I know that the Dragon firmware is built from the same blocks as the JTAG ICE mkII firmware (as far as the JTAG and debugWire interfaces are concerned), so it's for sure bound to the same 32 bits before/after restrictions.

avrs-admin commented 2 years ago

joerg_wunsch 2008-01-26 21:18:11