Lpc2000

Robert Adsett wrote:

> And this is where something else is needed. I haven't seen any way to 
> deal
>
>with timing issues with JTAG, for that the most effective way seems to be 
>pin toggling.  Then there are those problems that you cannot stop the 
>microprocessor since to do so will necessarily result in invalid results in 
>the best case and blown hardware or worse in other cases.  There are a 
>number of problems that the only effective way I've found to deal with is 
>to provide a data log that is later downloaded to a PC for analysis at a 
>safe or convenient point.
>  
>
Data log ... especially usefull todiscover these nice interrupt related 
bugs ...
But for timingrelated  stuff there are the ETM/ETB that can be part of 
the ARM core.
The lpc3000  contains an ETM, worked great for my timing issues on a 
926EJ-S.

>I'm not arguing against the use of JTAG, only that in some circumstances it 
>either cannot handle the problem or that other circumstances may force you 
>to work without it.
>
>I am a little worried that the presence of JTAG has meant that there is no 
>real ICE for the ARMs so that the most powerful tool in the development 
>arsenal is going to be missing when a really intractable problem 
>appears.  I expect ETM would cover most of the remaining territory but a 
>lot of the new parts don't have that support and of course it takes away 
>even more pins.
>  
>
For embedded processors real In Circuit Emulators are almost not 
feasible, you needto rely on stuff
like ETM of ETB.
Problem is support by JTAG debugger pods. Either not available or 
expensive ...
I have also not seen ARM7 with ETM yet (have not looked for it though) 
and I think the ARM9
is the first with ETM or ETB.

Rob