Lpc2000

No Dominic. My facts are not wrong. Below is what I stated and what 
Jaya replied. I asserted in Fact 2 that CRP decides if signals from 
JTAG will be allowed to act. This assumes JTAG is enabled and 
attempting to pass signals. Surely this is clear. I did not state 
signals to JTAG (from a debugger for example), I stated signals from 
JTAG, which in the context of Fact 1 clearly means bus signals.

I never stated CRP enables or disables JTAG. JTAG electronics 
operates independently. JTAG can be enabled and spinning uselessly 
because CRP has not enabled Debug.

I will not accept my comments are unfair. If someone posts to a group 
and imply a level of knowledge they do not possess then it is 
appropriate and fair to point this out. If you regard it a personal 
attack, that is not my problem, it still does not mean the comments 
are inappropriate. 

I have no intention of giving lessons in basic electronics. Yes I am 
aware you have put on the web a rather lengthy document concerned 
with JTAG.

I personally am really fed up the damaging effects of the poor level 
of insight of self proclaimed experts.

John Heenan


>  > Fact 1. JTAG hardware operates independently. Nothing JTAG does,
>  > including reset signals, will make the slightest bit of 
difference
>  > unless the signals JTAG passes are not blocked and so are 
allowed to
>  > act. Simple invertor and OR logic gates are perfectly adequate to
>  > block signals.
> 
> Could you explain what your point is in the above paragraph 
please.  I read 
> it a few times but cannot make out what you intend to point out.
> 
>  > Fact 2. The boot loader decides if CRP (Code Read Protection) is
>  > enabled and so decides if it will allow signals from JTAG to act.
> 
> Wrong.  JTAG signals are enabled or disabled on reset by pulling 
specific 
> GPIO pins low on boot [see notes on page 120 of 2294 user manual]. 
The boot 
> loader *disables* it, and then at a later time enables it if it 
thinks that 
> CRP is not enabled.


--- In lpc2000@yahoogroups.com, Dominic Rath <Dominic.Rath@...> wrote:
>
> Hello,
> 
> On Tuesday 28 February 2006 14:31, John Heenan wrote:
> > I don't believe I have got any facts wrong. The best 
interpretation
> > is that Jaya is very naive and has no idea just how deficient his
> > knowledge of electronics and the ARM architecture is and has no 
real
> > experience of how a support system works.
> >
> 
> You've listed a number of facts, and at least the second one (JTAG 
> enabled/disabled after reset) was definitely wrong - when Jaya said 
that "you 
> seem to have some of your facts wrong" he's perfectly right. 
Leaving this out 
> of your reply and instead running a personal attack on Jaya seems 
rather 
> unfair.
> 
> > ...
> >
> > John Heenan
> 
> Regards,
> 
> Dominic
>