Re: [UrJTAG-dev] TI tnetv1061

[snowweihua <sno...@so...>]

在 2009-03-03二的 21:13 +0100，Arnim Läuger写道：
> >> +# initbus ejtag from here produces a bunch of noise.
> >> +# But run it right after detect and all is well.
> >> +#initbus ejtag
> >> +endian little
> >>
> > I also find this problem on other CPUs. for example, brecis msp2000/msp2006. Log is attached here(I test on TNETV1060 cpu):
> > who can explain what is root cause ?
> 
> This part of UrJTAG is still new to me, but after having a look at the
> code for detect I got an idea about the reason for these errors.
> While detect examines the scan chain part for part, it includes the
> respective data files for each part. From how I understand detect's
> code, the whole detect phase is assumed to be a monolithic operation
> while the TAP is held in SHIFT-DR state. If the description file of a
> part that's included in between these shifts triggers any kind of TAP
> operation then it hits two problems:
> 1) TAP state SHIFT-DR, not IDLE as expected bus bus driver init()
>    -> reason for error messages before any reports related to bus
>       initialization
> 2) after include, once detect continues, the TAP state is not SHIFT-DR
>    anymore
>    -> reason for error messages after inclusion of part description
> 
> Any commands that perform TAP operations would trigger these issues, not
> just initbus though it's probably the most prominent candidate. In my
> opinion such commands must be avoided for part description files.
> Running initbus as a separate command after detect is the only solution
> at the moment.
> 
> Unfortunately, there's no automatic check available for this at the
> moment. I'll probably need to scan through the part files and disable
> these commands with a note.
> 
> Arnim
> 
I suggest please do not remove such command in include files. such
initbus, it let automatic check become true. I think we also can resolve
this problem after make two changes:
1. the start of codes in these command, reset to IDLE state when it
need.
2. back to caputure-DR state in detect

For example, for "initbus ejtag", I make a fix patch. Please review.
 
> 
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